In the crystal structure of the tetrapeptide Boc
0–Gly
1–ΔPhe
2–Gly
3–Phe
4–
p-NA (
p-NA is
para-nitroaniline), C
33H
36N
6O
8, there are two independent molecules differing in conformation in the asymmetric part of the unit cell. All the amino acids in the peptide are linked
trans to each other. The torsion angles in the main chain of both molecules are close to the values of the type β-II turn. Two intramolecular and three intermolecular N—H
O hydrogen bonds stabilize the conformation of each of the molecules.
Supporting information
CCDC reference: 160007
Boc–Gly–ΔPhe–Gly–Phe–p–NA was synthesized by the method described earlier
(Makowski et al., 2000). Crystals suitable for X–ray structure
analysis were grown from the ethyl acetate–diethyl ether (1:1)/hexane
solution.
The structure is non-centrosymmetric since both molecules have the same
configuration (S on carbon c19 and c19'). The refinement in
centrosymmetric P1 space group was tried and gave R ca 12%. In
the absence of any significant anomalous scatterers, the Friedel equivalents
were merged and the absolute configuration set by reference is that of natural
phenylalanine. H atoms were treated as riding with N—H 0.90 Å, C—H 0.96 Å.
Data collection: KUMA Diffraction Software (KUMA, 1998); cell refinement: KUMA Diffraction Software; data reduction: KUMA Diffraction Software; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 199b); molecular graphics: SHELXTL (Sheldrick, 1990); software used to prepare material for publication: SHELXL97.
Crystal data top
C33H36N6O8 | Z = 2 |
Mr = 644.68 | F(000) = 680 |
Triclinic, P1 | Dx = 1.323 Mg m−3 |
a = 10.328 (2) Å | Mo Kα radiation, λ = 0.71073 Å |
b = 11.605 (2) Å | Cell parameters from 29 reflections |
c = 14.796 (3) Å | θ = 5–12° |
α = 70.00 (3)° | µ = 0.10 mm−1 |
β = 86.37 (3)° | T = 105 K |
γ = 76.19 (3)° | Plate, yellow |
V = 1617.9 (5) Å3 | 0.5 × 0.4 × 0.3 mm |
Data collection top
KUMA KM–4 diffractometer | Rint = 0.029 |
Radiation source: fine-focus sealed tube | θmax = 26.1°, θmin = 1.5° |
Graphite monochromator | h = −12→12 |
ω scans | k = −13→12 |
11299 measured reflections | l = −16→16 |
5804 independent reflections | 2 standard reflections every 50 reflections |
5429 reflections with I > 2σ(I) | intensity decay: 0.3% |
Refinement top
Refinement on F2 | Secondary atom site location: difference Fourier map |
Least-squares matrix: full | Hydrogen site location: inferred from neighbouring sites |
R[F2 > 2σ(F2)] = 0.032 | H-atom parameters constrained |
wR(F2) = 0.105 | Calculated w = 1/[σ2(Fo2) + (0.0814P)2 + 0.1142P] where P = (Fo2 + 2Fc2)/3 |
S = 1.02 | (Δ/σ)max = 0.011 |
5804 reflections | Δρmax = 0.27 e Å−3 |
847 parameters | Δρmin = −0.37 e Å−3 |
3 restraints | Absolute structure: Flack (1983) |
Primary atom site location: structure-invariant direct methods | |
Crystal data top
C33H36N6O8 | γ = 76.19 (3)° |
Mr = 644.68 | V = 1617.9 (5) Å3 |
Triclinic, P1 | Z = 2 |
a = 10.328 (2) Å | Mo Kα radiation |
b = 11.605 (2) Å | µ = 0.10 mm−1 |
c = 14.796 (3) Å | T = 105 K |
α = 70.00 (3)° | 0.5 × 0.4 × 0.3 mm |
β = 86.37 (3)° | |
Data collection top
KUMA KM–4 diffractometer | Rint = 0.029 |
11299 measured reflections | 2 standard reflections every 50 reflections |
5804 independent reflections | intensity decay: 0.3% |
5429 reflections with I > 2σ(I) | |
Refinement top
R[F2 > 2σ(F2)] = 0.032 | 3 restraints |
wR(F2) = 0.105 | H-atom parameters constrained |
S = 1.02 | Δρmax = 0.27 e Å−3 |
5804 reflections | Δρmin = −0.37 e Å−3 |
847 parameters | Absolute structure: Flack (1983) |
Special details top
Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes)
are estimated using the full covariance matrix. The cell e.s.d.'s are taken
into account individually in the estimation of e.s.d.'s in distances, angles
and torsion angles; correlations between e.s.d.'s in cell parameters are only
used when they are defined by crystal symmetry. An approximate (isotropic)
treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s.
planes. |
Refinement. Refinement of F2 against ALL reflections. The weighted R-factor
wR and goodness of fit S are based on F2, conventional
R-factors R are based on F, with F set to zero for
negative F2. The threshold expression of F2 >
σ(F2) is used only for calculating R-factors(gt) etc.
and is not relevant to the choice of reflections for refinement.
R-factors based on F2 are statistically about twice as large
as those based on F, and R- factors based on ALL data will be
even larger. |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
O1 | 0.6678 (2) | 0.48239 (18) | 0.85623 (15) | 0.0261 (4) | |
O2 | 0.64381 (19) | 0.28032 (18) | 0.89527 (14) | 0.0231 (4) | |
O3 | 0.75597 (17) | 0.21362 (16) | 1.10279 (14) | 0.0204 (4) | |
O4 | 0.96448 (17) | −0.11258 (17) | 1.11484 (13) | 0.0195 (4) | |
O5 | 0.92384 (18) | −0.19111 (18) | 0.93694 (14) | 0.0234 (4) | |
O6 | 1.2760 (2) | −0.49850 (19) | 1.06290 (16) | 0.0308 (5) | |
O7 | 1.0028 (4) | −0.5612 (3) | 1.5550 (2) | 0.0590 (8) | |
O8 | 1.0491 (4) | −0.7348 (3) | 1.5246 (2) | 0.0625 (9) | |
N1 | 0.5562 (2) | 0.4010 (2) | 0.98608 (17) | 0.0208 (5) | |
H1A | 0.5321 | 0.4790 | 0.9897 | 0.025* | |
N2 | 0.6310 (2) | 0.0724 (2) | 1.12064 (16) | 0.0185 (5) | |
H2D | 0.5493 | 0.0597 | 1.1164 | 0.022* | |
N3 | 0.8351 (2) | 0.0262 (2) | 0.99107 (16) | 0.0190 (5) | |
H3D | 0.7554 | 0.0776 | 0.9683 | 0.023* | |
N4 | 1.1315 (2) | −0.1684 (2) | 0.94200 (16) | 0.0189 (5) | |
H4D | 1.1857 | −0.1189 | 0.9439 | 0.023* | |
N5 | 1.1403 (2) | −0.3513 (2) | 1.11740 (17) | 0.0215 (5) | |
H5A | 1.1031 | −0.2682 | 1.0999 | 0.026* | |
N6 | 1.0384 (3) | −0.6216 (3) | 1.5004 (2) | 0.0427 (7) | |
C1 | 0.7438 (3) | 0.4809 (3) | 0.7686 (2) | 0.0287 (6) | |
C2 | 0.6528 (4) | 0.4781 (3) | 0.6940 (2) | 0.0401 (8) | |
H2A | 0.5768 | 0.5480 | 0.6824 | 0.048* | |
H2B | 0.7002 | 0.4836 | 0.6353 | 0.048* | |
H2C | 0.6237 | 0.4007 | 0.7169 | 0.048* | |
C3 | 0.7834 (4) | 0.6071 (3) | 0.7361 (3) | 0.0420 (8) | |
H3A | 0.7047 | 0.6745 | 0.7215 | 0.050* | |
H3B | 0.8339 | 0.6115 | 0.7866 | 0.050* | |
H3C | 0.8368 | 0.6146 | 0.6798 | 0.050* | |
C4 | 0.8680 (3) | 0.3741 (3) | 0.7920 (3) | 0.0379 (8) | |
H4A | 0.8420 | 0.2951 | 0.8124 | 0.045* | |
H4B | 0.9215 | 0.3812 | 0.7358 | 0.045* | |
H4C | 0.9186 | 0.3781 | 0.8426 | 0.045* | |
C5 | 0.6243 (3) | 0.3792 (2) | 0.9112 (2) | 0.0208 (6) | |
C6 | 0.5219 (3) | 0.2948 (2) | 1.0608 (2) | 0.0209 (5) | |
H6A | 0.4590 | 0.2635 | 1.0360 | 0.025* | |
H6B | 0.4814 | 0.3210 | 1.1129 | 0.025* | |
C7 | 0.6473 (2) | 0.1909 (2) | 1.09708 (19) | 0.0178 (5) | |
C8 | 0.7414 (2) | −0.0328 (2) | 1.15171 (19) | 0.0176 (5) | |
C9 | 0.7452 (3) | −0.1302 (3) | 1.2335 (2) | 0.0195 (5) | |
H9A | 0.8209 | −0.1998 | 1.2420 | 0.023* | |
C10 | 0.6493 (3) | −0.1451 (2) | 1.31214 (19) | 0.0201 (5) | |
C11 | 0.5685 (3) | −0.0447 (3) | 1.3351 (2) | 0.0238 (6) | |
H11A | 0.5699 | 0.0403 | 1.2960 | 0.029* | |
C12 | 0.4859 (3) | −0.0665 (3) | 1.4138 (2) | 0.0286 (6) | |
H12A | 0.4328 | 0.0035 | 1.4299 | 0.034* | |
C13 | 0.4789 (3) | −0.1888 (3) | 1.4696 (2) | 0.0307 (6) | |
H13A | 0.4206 | −0.2033 | 1.5235 | 0.037* | |
C14 | 0.5573 (3) | −0.2886 (3) | 1.4463 (2) | 0.0307 (7) | |
H14A | 0.5521 | −0.3732 | 1.4834 | 0.037* | |
C15 | 0.6438 (3) | −0.2678 (3) | 1.3696 (2) | 0.0259 (6) | |
H15A | 0.7004 | −0.3383 | 1.3559 | 0.031* | |
C16 | 0.8542 (3) | −0.0404 (2) | 1.08456 (19) | 0.0169 (5) | |
C17 | 0.9459 (3) | 0.0139 (2) | 0.9264 (2) | 0.0203 (5) | |
H17A | 1.0155 | 0.0464 | 0.9419 | 0.024* | |
H17B | 0.9167 | 0.0620 | 0.8612 | 0.024* | |
C18 | 0.9993 (2) | −0.1239 (2) | 0.93622 (18) | 0.0180 (5) | |
C19 | 1.1872 (3) | −0.2971 (2) | 0.94487 (19) | 0.0195 (5) | |
H19A | 1.1230 | −0.3195 | 0.9138 | 0.023* | |
C20 | 1.3144 (3) | −0.3058 (3) | 0.8864 (2) | 0.0230 (6) | |
H20A | 1.3385 | −0.3875 | 0.8795 | 0.028* | |
H20B | 1.3853 | −0.2984 | 0.9214 | 0.028* | |
C21 | 1.3013 (3) | −0.2058 (3) | 0.7872 (2) | 0.0239 (6) | |
C22 | 1.1854 (3) | −0.1610 (3) | 0.7320 (2) | 0.0360 (7) | |
H22A | 1.1102 | −0.1975 | 0.7544 | 0.043* | |
C23 | 1.1765 (3) | −0.0634 (4) | 0.6445 (2) | 0.0430 (9) | |
H23A | 1.0952 | −0.0335 | 0.6069 | 0.052* | |
C24 | 1.2828 (4) | −0.0094 (3) | 0.6110 (2) | 0.0396 (8) | |
H24A | 1.2749 | 0.0601 | 0.5516 | 0.047* | |
C25 | 1.4008 (4) | −0.0552 (3) | 0.6638 (2) | 0.0380 (8) | |
H25A | 1.4768 | −0.0204 | 0.6402 | 0.046* | |
C26 | 1.4091 (3) | −0.1525 (3) | 0.7507 (2) | 0.0301 (6) | |
H26A | 1.4915 | −0.1841 | 0.7871 | 0.036* | |
C27 | 1.2074 (3) | −0.3924 (3) | 1.0477 (2) | 0.0217 (6) | |
C28 | 1.1219 (3) | −0.4242 (3) | 1.2139 (2) | 0.0217 (6) | |
C29 | 1.0882 (3) | −0.3615 (3) | 1.2801 (2) | 0.0253 (6) | |
H29A | 1.0833 | −0.2727 | 1.2603 | 0.030* | |
C30 | 1.0620 (3) | −0.4258 (3) | 1.3743 (2) | 0.0289 (6) | |
H30A | 1.0391 | −0.3826 | 1.4201 | 0.035* | |
C31 | 1.0694 (3) | −0.5534 (3) | 1.4009 (2) | 0.0320 (7) | |
C32 | 1.1042 (4) | −0.6176 (3) | 1.3375 (2) | 0.0362 (7) | |
H32A | 1.1104 | −0.7067 | 1.3583 | 0.043* | |
C33 | 1.1301 (3) | −0.5527 (3) | 1.2421 (2) | 0.0312 (7) | |
H33A | 1.1536 | −0.5965 | 1.1967 | 0.037* | |
O1' | 0.6586 (2) | 0.37360 (18) | 0.26175 (15) | 0.0264 (4) | |
O2' | 0.6904 (2) | 0.57357 (19) | 0.22206 (14) | 0.0269 (4) | |
O3' | 0.55904 (18) | 0.62678 (17) | 0.02787 (14) | 0.0216 (4) | |
O4' | 0.33376 (17) | 0.93925 (16) | −0.00879 (13) | 0.0188 (4) | |
O5' | 0.35743 (17) | 1.05629 (17) | 0.15589 (14) | 0.0202 (4) | |
O6' | 0.0685 (2) | 1.34365 (19) | 0.04303 (16) | 0.0319 (5) | |
O7' | 0.3312 (3) | 1.4137 (3) | −0.4518 (2) | 0.0592 (8) | |
O8' | 0.3110 (3) | 1.5789 (3) | −0.4111 (2) | 0.0522 (7) | |
N1' | 0.7724 (2) | 0.4505 (2) | 0.13141 (17) | 0.0208 (5) | |
H1'A | 0.8000 | 0.3716 | 0.1298 | 0.025* | |
N2' | 0.6757 (2) | 0.7780 (2) | −0.01392 (16) | 0.0192 (5) | |
H2'D | 0.7568 | 0.7951 | −0.0179 | 0.023* | |
N3' | 0.4731 (2) | 0.8286 (2) | 0.11702 (16) | 0.0194 (5) | |
H3'D | 0.5562 | 0.7876 | 0.1400 | 0.023* | |
N4' | 0.1611 (2) | 1.0054 (2) | 0.15114 (16) | 0.0178 (4) | |
H4'D | 0.1216 | 0.9444 | 0.1504 | 0.021* | |
N5' | 0.1740 (2) | 1.1927 (2) | −0.02007 (16) | 0.0201 (5) | |
H5'A | 0.1987 | 1.1086 | −0.0060 | 0.024* | |
N6' | 0.3068 (3) | 1.4684 (3) | −0.3931 (2) | 0.0390 (7) | |
C1' | 0.5749 (3) | 0.3806 (3) | 0.3453 (2) | 0.0278 (6) | |
C2' | 0.6605 (4) | 0.3823 (3) | 0.4236 (2) | 0.0384 (8) | |
H2'A | 0.7337 | 0.3095 | 0.4393 | 0.046* | |
H2'B | 0.6942 | 0.4572 | 0.4019 | 0.046* | |
H2'C | 0.6078 | 0.3808 | 0.4797 | 0.046* | |
C3' | 0.4562 (3) | 0.4928 (3) | 0.3153 (2) | 0.0333 (7) | |
H3'A | 0.4866 | 0.5695 | 0.2963 | 0.040* | |
H3'B | 0.4095 | 0.4900 | 0.2623 | 0.040* | |
H3'C | 0.3973 | 0.4896 | 0.3686 | 0.040* | |
C4' | 0.5268 (4) | 0.2591 (3) | 0.3752 (3) | 0.0406 (8) | |
H4'A | 0.6021 | 0.1884 | 0.3940 | 0.049* | |
H4'B | 0.4679 | 0.2558 | 0.4284 | 0.049* | |
H4'C | 0.4802 | 0.2562 | 0.3222 | 0.049* | |
C5' | 0.7055 (3) | 0.4741 (2) | 0.20734 (19) | 0.0210 (6) | |
C6' | 0.7977 (3) | 0.5582 (3) | 0.0533 (2) | 0.0227 (6) | |
H6'A | 0.8357 | 0.5322 | 0.0005 | 0.027* | |
H6'B | 0.8599 | 0.5941 | 0.0742 | 0.027* | |
C7' | 0.6661 (3) | 0.6563 (2) | 0.02113 (19) | 0.0180 (5) | |
C8' | 0.5625 (3) | 0.8791 (2) | −0.0441 (2) | 0.0187 (5) | |
C9' | 0.5566 (3) | 0.9801 (3) | −0.12358 (19) | 0.0206 (5) | |
H9'A | 0.4788 | 1.0471 | −0.1297 | 0.025* | |
C10' | 0.6501 (3) | 1.0047 (3) | −0.2026 (2) | 0.0213 (6) | |
C11' | 0.7322 (3) | 0.9106 (3) | −0.2318 (2) | 0.0240 (6) | |
H11B | 0.7341 | 0.8238 | −0.1961 | 0.029* | |
C12' | 0.8119 (3) | 0.9404 (3) | −0.3118 (2) | 0.0288 (6) | |
H12B | 0.8660 | 0.8746 | −0.3324 | 0.035* | |
C13' | 0.8133 (3) | 1.0649 (3) | −0.3623 (2) | 0.0333 (7) | |
H13B | 0.8689 | 1.0854 | −0.4173 | 0.040* | |
C14' | 0.7349 (3) | 1.1593 (3) | −0.3330 (2) | 0.0322 (7) | |
H14B | 0.7378 | 1.2455 | −0.3667 | 0.039* | |
C15' | 0.6515 (3) | 1.1300 (3) | −0.2550 (2) | 0.0265 (6) | |
H15B | 0.5944 | 1.1967 | −0.2369 | 0.032* | |
C16' | 0.4487 (3) | 0.8813 (2) | 0.02270 (19) | 0.0183 (5) | |
C17' | 0.3628 (3) | 0.8389 (2) | 0.1823 (2) | 0.0199 (5) | |
H17C | 0.3954 | 0.8018 | 0.2477 | 0.024* | |
H17D | 0.3001 | 0.7941 | 0.1737 | 0.024* | |
C18' | 0.2944 (2) | 0.9770 (2) | 0.16192 (18) | 0.0170 (5) | |
C19' | 0.0775 (2) | 1.1295 (2) | 0.14051 (19) | 0.0185 (5) | |
H19B | −0.0120 | 1.1248 | 0.1313 | 0.022* | |
C20' | 0.0765 (3) | 1.1634 (3) | 0.2319 (2) | 0.0221 (5) | |
H20C | 0.0141 | 1.2425 | 0.2235 | 0.026* | |
H20D | 0.1634 | 1.1728 | 0.2430 | 0.026* | |
C21' | 0.0384 (3) | 1.0621 (3) | 0.3184 (2) | 0.0227 (6) | |
C22' | 0.1355 (3) | 0.9589 (3) | 0.3704 (2) | 0.0293 (6) | |
H22B | 0.2277 | 0.9555 | 0.3549 | 0.035* | |
C23' | 0.1005 (4) | 0.8602 (3) | 0.4448 (2) | 0.0373 (7) | |
H23B | 0.1685 | 0.7888 | 0.4796 | 0.045* | |
C24' | −0.0307 (4) | 0.8646 (3) | 0.4688 (2) | 0.0363 (7) | |
H24B | −0.0548 | 0.7962 | 0.5198 | 0.044* | |
C25' | −0.1285 (3) | 0.9680 (3) | 0.4191 (2) | 0.0351 (7) | |
H25B | −0.2203 | 0.9723 | 0.4365 | 0.042* | |
C26' | −0.0938 (3) | 1.0662 (3) | 0.3436 (2) | 0.0284 (6) | |
H26B | −0.1623 | 1.1373 | 0.3091 | 0.034* | |
C27' | 0.1087 (3) | 1.2343 (3) | 0.0505 (2) | 0.0211 (6) | |
C28' | 0.2067 (3) | 1.2663 (3) | −0.1123 (2) | 0.0216 (6) | |
C29' | 0.2286 (3) | 1.2102 (3) | −0.1830 (2) | 0.0244 (6) | |
H29B | 0.2205 | 1.1249 | −0.1675 | 0.029* | |
C30' | 0.2615 (3) | 1.2759 (3) | −0.2752 (2) | 0.0277 (6) | |
H30B | 0.2770 | 1.2370 | −0.3239 | 0.033* | |
C31' | 0.2718 (3) | 1.3985 (3) | −0.2954 (2) | 0.0298 (7) | |
C32' | 0.2516 (3) | 1.4561 (3) | −0.2264 (2) | 0.0327 (7) | |
H32B | 0.2601 | 1.5414 | −0.2425 | 0.039* | |
C33' | 0.2187 (3) | 1.3898 (3) | −0.1334 (2) | 0.0282 (6) | |
H33B | 0.2046 | 1.4288 | −0.0848 | 0.034* | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
O1 | 0.0330 (11) | 0.0168 (10) | 0.0274 (11) | −0.0071 (8) | 0.0067 (8) | −0.0061 (8) |
O2 | 0.0283 (10) | 0.0152 (10) | 0.0248 (10) | −0.0029 (7) | 0.0017 (8) | −0.0069 (7) |
O3 | 0.0166 (9) | 0.0148 (9) | 0.0285 (10) | −0.0020 (7) | 0.0011 (7) | −0.0070 (7) |
O4 | 0.0159 (9) | 0.0157 (9) | 0.0240 (9) | −0.0004 (7) | −0.0008 (7) | −0.0052 (7) |
O5 | 0.0165 (9) | 0.0217 (10) | 0.0339 (11) | −0.0051 (7) | 0.0017 (8) | −0.0116 (8) |
O6 | 0.0296 (11) | 0.0168 (10) | 0.0379 (12) | 0.0008 (8) | 0.0084 (9) | −0.0045 (9) |
O7 | 0.092 (2) | 0.0437 (16) | 0.0324 (14) | −0.0080 (15) | 0.0200 (14) | −0.0101 (12) |
O8 | 0.112 (3) | 0.0268 (14) | 0.0399 (15) | −0.0199 (15) | 0.0161 (15) | −0.0003 (11) |
N1 | 0.0213 (11) | 0.0130 (11) | 0.0247 (12) | −0.0011 (8) | 0.0010 (9) | −0.0042 (9) |
N2 | 0.0153 (10) | 0.0127 (11) | 0.0258 (12) | −0.0019 (8) | 0.0001 (8) | −0.0053 (9) |
N3 | 0.0165 (10) | 0.0144 (11) | 0.0233 (12) | 0.0004 (8) | 0.0010 (9) | −0.0055 (9) |
N4 | 0.0165 (10) | 0.0148 (11) | 0.0252 (12) | −0.0030 (8) | 0.0020 (8) | −0.0071 (9) |
N5 | 0.0226 (11) | 0.0147 (11) | 0.0239 (12) | −0.0008 (8) | −0.0012 (9) | −0.0046 (9) |
N6 | 0.061 (2) | 0.0298 (16) | 0.0298 (15) | −0.0082 (13) | 0.0065 (13) | −0.0028 (12) |
C1 | 0.0390 (16) | 0.0170 (14) | 0.0266 (15) | −0.0045 (12) | 0.0081 (12) | −0.0056 (11) |
C2 | 0.057 (2) | 0.0287 (17) | 0.0273 (17) | −0.0061 (15) | −0.0017 (15) | −0.0025 (13) |
C3 | 0.057 (2) | 0.0283 (18) | 0.0386 (19) | −0.0165 (15) | 0.0202 (16) | −0.0078 (14) |
C4 | 0.0342 (17) | 0.0337 (18) | 0.0365 (18) | −0.0016 (13) | 0.0130 (14) | −0.0067 (14) |
C5 | 0.0193 (12) | 0.0150 (13) | 0.0244 (14) | −0.0006 (9) | −0.0034 (10) | −0.0035 (10) |
C6 | 0.0172 (12) | 0.0149 (13) | 0.0268 (14) | −0.0004 (9) | 0.0025 (10) | −0.0049 (10) |
C7 | 0.0157 (12) | 0.0163 (13) | 0.0199 (12) | −0.0010 (9) | 0.0036 (9) | −0.0067 (10) |
C8 | 0.0159 (12) | 0.0129 (13) | 0.0236 (13) | −0.0027 (9) | 0.0006 (10) | −0.0062 (10) |
C9 | 0.0180 (12) | 0.0161 (13) | 0.0242 (13) | −0.0014 (9) | −0.0006 (10) | −0.0081 (10) |
C10 | 0.0192 (12) | 0.0191 (14) | 0.0205 (13) | −0.0045 (10) | −0.0011 (10) | −0.0043 (10) |
C11 | 0.0248 (14) | 0.0165 (13) | 0.0284 (15) | −0.0043 (10) | 0.0026 (11) | −0.0061 (11) |
C12 | 0.0293 (15) | 0.0255 (16) | 0.0305 (16) | −0.0043 (12) | 0.0065 (12) | −0.0112 (12) |
C13 | 0.0322 (15) | 0.0335 (16) | 0.0245 (15) | −0.0112 (12) | 0.0064 (12) | −0.0060 (12) |
C14 | 0.0417 (17) | 0.0222 (15) | 0.0234 (15) | −0.0094 (12) | 0.0021 (12) | −0.0007 (11) |
C15 | 0.0302 (14) | 0.0195 (14) | 0.0254 (14) | −0.0024 (11) | −0.0016 (11) | −0.0065 (11) |
C16 | 0.0184 (12) | 0.0101 (12) | 0.0238 (13) | −0.0048 (9) | 0.0001 (10) | −0.0066 (10) |
C17 | 0.0190 (12) | 0.0158 (13) | 0.0223 (14) | −0.0017 (10) | 0.0018 (10) | −0.0037 (10) |
C18 | 0.0177 (12) | 0.0178 (13) | 0.0175 (12) | −0.0041 (10) | 0.0025 (9) | −0.0049 (10) |
C19 | 0.0180 (12) | 0.0164 (13) | 0.0244 (14) | −0.0018 (9) | −0.0007 (10) | −0.0083 (10) |
C20 | 0.0182 (12) | 0.0250 (14) | 0.0264 (14) | −0.0017 (10) | 0.0014 (10) | −0.0117 (11) |
C21 | 0.0233 (13) | 0.0216 (14) | 0.0259 (14) | 0.0000 (10) | 0.0024 (11) | −0.0104 (11) |
C22 | 0.0218 (14) | 0.050 (2) | 0.0297 (16) | −0.0042 (13) | 0.0027 (12) | −0.0088 (14) |
C23 | 0.0279 (16) | 0.055 (2) | 0.0291 (17) | 0.0064 (14) | 0.0003 (13) | −0.0042 (15) |
C24 | 0.047 (2) | 0.0366 (18) | 0.0251 (16) | 0.0015 (14) | 0.0086 (14) | −0.0068 (13) |
C25 | 0.0450 (19) | 0.042 (2) | 0.0292 (17) | −0.0185 (15) | 0.0087 (14) | −0.0105 (14) |
C26 | 0.0302 (15) | 0.0353 (17) | 0.0268 (15) | −0.0101 (12) | −0.0007 (12) | −0.0113 (12) |
C27 | 0.0174 (12) | 0.0167 (13) | 0.0292 (15) | −0.0043 (10) | 0.0031 (10) | −0.0057 (11) |
C28 | 0.0191 (12) | 0.0186 (14) | 0.0250 (14) | −0.0018 (10) | −0.0015 (10) | −0.0056 (11) |
C29 | 0.0261 (14) | 0.0157 (14) | 0.0289 (15) | −0.0017 (10) | −0.0017 (11) | −0.0026 (11) |
C30 | 0.0323 (15) | 0.0256 (15) | 0.0261 (16) | −0.0008 (12) | −0.0004 (12) | −0.0091 (12) |
C31 | 0.0401 (17) | 0.0238 (16) | 0.0268 (16) | −0.0068 (12) | 0.0026 (12) | −0.0025 (12) |
C32 | 0.054 (2) | 0.0192 (15) | 0.0325 (17) | −0.0106 (13) | 0.0037 (14) | −0.0047 (12) |
C33 | 0.0424 (17) | 0.0201 (15) | 0.0298 (16) | −0.0078 (12) | 0.0016 (13) | −0.0066 (12) |
O1' | 0.0339 (11) | 0.0153 (10) | 0.0283 (11) | −0.0056 (8) | 0.0064 (8) | −0.0062 (8) |
O2' | 0.0331 (11) | 0.0196 (11) | 0.0281 (11) | −0.0044 (8) | 0.0006 (8) | −0.0094 (8) |
O3' | 0.0207 (9) | 0.0157 (9) | 0.0273 (10) | −0.0032 (7) | −0.0001 (7) | −0.0065 (7) |
O4' | 0.0154 (8) | 0.0159 (9) | 0.0239 (9) | −0.0019 (7) | −0.0005 (7) | −0.0063 (7) |
O5' | 0.0169 (9) | 0.0176 (9) | 0.0262 (10) | −0.0040 (7) | 0.0007 (7) | −0.0074 (7) |
O6' | 0.0383 (12) | 0.0150 (10) | 0.0348 (12) | 0.0003 (8) | 0.0089 (9) | −0.0045 (8) |
O7' | 0.085 (2) | 0.0523 (18) | 0.0302 (14) | −0.0145 (15) | 0.0223 (14) | −0.0055 (12) |
O8' | 0.0685 (18) | 0.0356 (15) | 0.0390 (14) | −0.0180 (12) | 0.0072 (12) | 0.0075 (11) |
N1' | 0.0207 (11) | 0.0120 (11) | 0.0272 (12) | −0.0001 (8) | 0.0001 (9) | −0.0059 (9) |
N2' | 0.0147 (10) | 0.0143 (11) | 0.0259 (12) | −0.0015 (8) | 0.0016 (8) | −0.0048 (9) |
N3' | 0.0168 (10) | 0.0153 (11) | 0.0229 (12) | 0.0002 (8) | 0.0011 (9) | −0.0050 (9) |
N4' | 0.0161 (10) | 0.0133 (11) | 0.0224 (11) | −0.0026 (8) | 0.0004 (8) | −0.0045 (8) |
N5' | 0.0240 (11) | 0.0133 (11) | 0.0197 (11) | −0.0024 (8) | 0.0015 (9) | −0.0029 (9) |
N6' | 0.0387 (15) | 0.0374 (17) | 0.0283 (15) | −0.0069 (12) | 0.0072 (11) | 0.0023 (12) |
C1' | 0.0374 (16) | 0.0172 (14) | 0.0250 (15) | −0.0050 (12) | 0.0082 (12) | −0.0047 (11) |
C2' | 0.053 (2) | 0.0250 (17) | 0.0286 (16) | 0.0007 (14) | −0.0013 (14) | −0.0047 (13) |
C3' | 0.0333 (16) | 0.0250 (16) | 0.0349 (17) | −0.0025 (12) | 0.0070 (13) | −0.0055 (13) |
C4' | 0.054 (2) | 0.0224 (16) | 0.044 (2) | −0.0143 (14) | 0.0201 (16) | −0.0089 (14) |
C5' | 0.0220 (13) | 0.0159 (14) | 0.0213 (13) | −0.0010 (10) | −0.0025 (10) | −0.0031 (10) |
C6' | 0.0193 (12) | 0.0167 (13) | 0.0282 (15) | −0.0018 (10) | 0.0013 (10) | −0.0042 (11) |
C7' | 0.0213 (13) | 0.0137 (13) | 0.0189 (12) | −0.0021 (10) | 0.0015 (10) | −0.0067 (10) |
C8' | 0.0177 (12) | 0.0136 (13) | 0.0253 (14) | −0.0022 (10) | −0.0010 (10) | −0.0079 (10) |
C9' | 0.0200 (12) | 0.0168 (13) | 0.0234 (14) | −0.0018 (10) | 0.0001 (10) | −0.0063 (10) |
C10' | 0.0214 (13) | 0.0185 (14) | 0.0214 (13) | −0.0037 (10) | −0.0033 (10) | −0.0035 (11) |
C11' | 0.0254 (14) | 0.0198 (14) | 0.0253 (14) | −0.0036 (10) | 0.0007 (11) | −0.0066 (11) |
C12' | 0.0259 (14) | 0.0290 (16) | 0.0294 (15) | −0.0026 (11) | 0.0031 (11) | −0.0101 (12) |
C13' | 0.0341 (16) | 0.0340 (17) | 0.0252 (15) | −0.0066 (13) | 0.0057 (12) | −0.0035 (12) |
C14' | 0.0411 (17) | 0.0264 (16) | 0.0248 (15) | −0.0111 (13) | 0.0029 (13) | −0.0014 (12) |
C15' | 0.0345 (15) | 0.0194 (14) | 0.0228 (14) | −0.0040 (11) | 0.0004 (11) | −0.0052 (11) |
C16' | 0.0207 (13) | 0.0087 (12) | 0.0267 (14) | −0.0042 (9) | −0.0003 (10) | −0.0067 (10) |
C17' | 0.0187 (12) | 0.0150 (13) | 0.0232 (13) | −0.0033 (9) | 0.0029 (10) | −0.0038 (10) |
C18' | 0.0173 (12) | 0.0150 (12) | 0.0163 (12) | −0.0029 (9) | 0.0006 (9) | −0.0027 (9) |
C19' | 0.0154 (12) | 0.0136 (12) | 0.0237 (13) | −0.0017 (9) | 0.0018 (10) | −0.0040 (10) |
C20' | 0.0182 (12) | 0.0198 (13) | 0.0265 (14) | −0.0018 (10) | 0.0030 (10) | −0.0079 (10) |
C21' | 0.0256 (13) | 0.0220 (14) | 0.0209 (13) | −0.0041 (10) | 0.0018 (10) | −0.0091 (11) |
C22' | 0.0267 (14) | 0.0318 (16) | 0.0256 (15) | −0.0027 (12) | 0.0027 (11) | −0.0079 (12) |
C23' | 0.0478 (19) | 0.0266 (16) | 0.0269 (16) | 0.0018 (14) | 0.0009 (13) | −0.0028 (12) |
C24' | 0.054 (2) | 0.0323 (17) | 0.0240 (16) | −0.0172 (15) | 0.0072 (14) | −0.0075 (12) |
C25' | 0.0338 (16) | 0.0453 (19) | 0.0281 (16) | −0.0170 (14) | 0.0051 (12) | −0.0100 (13) |
C26' | 0.0253 (14) | 0.0331 (16) | 0.0253 (14) | −0.0056 (12) | 0.0021 (11) | −0.0091 (12) |
C27' | 0.0179 (13) | 0.0163 (14) | 0.0263 (14) | −0.0023 (10) | 0.0003 (10) | −0.0048 (10) |
C28' | 0.0178 (12) | 0.0205 (14) | 0.0225 (14) | −0.0027 (10) | −0.0016 (10) | −0.0031 (11) |
C29' | 0.0233 (13) | 0.0212 (14) | 0.0251 (14) | −0.0006 (10) | 0.0013 (11) | −0.0067 (11) |
C30' | 0.0298 (14) | 0.0222 (15) | 0.0242 (15) | −0.0004 (11) | 0.0010 (11) | −0.0031 (12) |
C31' | 0.0305 (15) | 0.0285 (16) | 0.0205 (14) | −0.0029 (12) | 0.0022 (11) | 0.0011 (12) |
C32' | 0.0398 (17) | 0.0219 (15) | 0.0311 (16) | −0.0109 (12) | 0.0031 (13) | −0.0001 (12) |
C33' | 0.0342 (15) | 0.0235 (15) | 0.0268 (15) | −0.0103 (11) | 0.0041 (12) | −0.0065 (11) |
Geometric parameters (Å, º) top
O1—C5 | 1.356 (3) | O1'—C5' | 1.349 (3) |
O1—C1 | 1.476 (4) | O1'—C1' | 1.477 (4) |
O2—C5 | 1.218 (4) | O2'—C5' | 1.220 (3) |
O3—C7 | 1.227 (3) | O3'—C7' | 1.222 (3) |
O4—C16 | 1.246 (3) | O4'—C16' | 1.246 (3) |
O5—C18 | 1.224 (3) | O5'—C18' | 1.225 (3) |
O6—C27 | 1.217 (3) | O6'—C27' | 1.206 (3) |
O7—N6 | 1.227 (4) | O7'—N6' | 1.221 (4) |
O8—N6 | 1.217 (4) | O8'—N6' | 1.229 (4) |
N1—C5 | 1.340 (4) | N1'—C5' | 1.355 (4) |
N1—C6 | 1.447 (3) | N1'—C6' | 1.448 (3) |
N1—H1A | 0.9000 | N1'—H1'A | 0.9000 |
N2—C7 | 1.348 (4) | N2'—C7' | 1.353 (3) |
N2—C8 | 1.421 (3) | N2'—C8' | 1.413 (3) |
N2—H2D | 0.9000 | N2'—H2'D | 0.9000 |
N3—C16 | 1.334 (4) | N3'—C16' | 1.331 (4) |
N3—C17 | 1.456 (3) | N3'—C17' | 1.456 (3) |
N3—H3D | 0.9000 | N3'—H3'D | 0.9000 |
N4—C18 | 1.337 (3) | N4'—C18' | 1.343 (3) |
N4—C19 | 1.454 (3) | N4'—C19' | 1.454 (3) |
N4—H4D | 0.9000 | N4'—H4'D | 0.9000 |
N5—C27 | 1.364 (4) | N5'—C27' | 1.370 (4) |
N5—C28 | 1.416 (4) | N5'—C28' | 1.410 (4) |
N5—H5A | 0.9000 | N5'—H5'A | 0.9000 |
N6—C31 | 1.470 (4) | N6'—C31' | 1.466 (4) |
C1—C2 | 1.508 (5) | C1'—C2' | 1.509 (5) |
C1—C4 | 1.518 (4) | C1'—C4' | 1.520 (4) |
C1—C3 | 1.524 (4) | C1'—C3' | 1.519 (4) |
C2—H2A | 0.9600 | C2'—H2'A | 0.9600 |
C2—H2B | 0.9600 | C2'—H2'B | 0.9599 |
C2—H2C | 0.9600 | C2'—H2'C | 0.9600 |
C3—H3A | 0.9600 | C3'—H3'A | 0.9600 |
C3—H3B | 0.9599 | C3'—H3'B | 0.9600 |
C3—H3C | 0.9600 | C3'—H3'C | 0.9600 |
C4—H4A | 0.9600 | C4'—H4'A | 0.9600 |
C4—H4B | 0.9600 | C4'—H4'B | 0.9600 |
C4—H4C | 0.9600 | C4'—H4'C | 0.9600 |
C6—C7 | 1.523 (3) | C6'—C7' | 1.530 (4) |
C6—H6A | 0.9600 | C6'—H6'A | 0.9600 |
C6—H6B | 0.9601 | C6'—H6'B | 0.9600 |
C8—C9 | 1.339 (4) | C8'—C9' | 1.339 (4) |
C8—C16 | 1.489 (4) | C8'—C16' | 1.488 (4) |
C9—C10 | 1.470 (4) | C9'—C10' | 1.463 (4) |
C9—H9A | 0.9600 | C9'—H9'A | 0.9600 |
C10—C11 | 1.393 (4) | C10'—C11' | 1.390 (4) |
C10—C15 | 1.399 (4) | C10'—C15' | 1.398 (4) |
C11—C12 | 1.387 (4) | C11'—C12' | 1.390 (4) |
C11—H11A | 0.9600 | C11'—H11B | 0.9600 |
C12—C13 | 1.393 (4) | C12'—C13' | 1.385 (5) |
C12—H12A | 0.9600 | C12'—H12B | 0.9600 |
C13—C14 | 1.381 (5) | C13'—C14' | 1.379 (5) |
C13—H13A | 0.9600 | C13'—H13B | 0.9600 |
C14—C15 | 1.390 (4) | C14'—C15' | 1.391 (4) |
C14—H14A | 0.9600 | C14'—H14B | 0.9600 |
C15—H15A | 0.9601 | C15'—H15B | 0.9600 |
C17—C18 | 1.521 (4) | C17'—C18' | 1.522 (4) |
C17—H17A | 0.9600 | C17'—H17C | 0.9600 |
C17—H17B | 0.9600 | C17'—H17D | 0.9600 |
C19—C20 | 1.529 (4) | C19'—C20' | 1.531 (4) |
C19—C27 | 1.537 (4) | C19'—C27' | 1.543 (4) |
C19—H19A | 0.9600 | C19'—H19B | 0.9600 |
C20—C21 | 1.518 (4) | C20'—C21' | 1.517 (4) |
C20—H20A | 0.9600 | C20'—H20C | 0.9600 |
C20—H20B | 0.9600 | C20'—H20D | 0.9600 |
C21—C22 | 1.380 (4) | C21'—C26' | 1.386 (4) |
C21—C26 | 1.393 (4) | C21'—C22' | 1.388 (4) |
C22—C23 | 1.390 (5) | C22'—C23' | 1.392 (4) |
C22—H22A | 0.9599 | C22'—H22B | 0.9600 |
C23—C24 | 1.375 (5) | C23'—C24' | 1.373 (5) |
C23—H23A | 0.9600 | C23'—H23B | 0.9600 |
C24—C25 | 1.380 (5) | C24'—C25' | 1.383 (5) |
C24—H24A | 0.9600 | C24'—H24B | 0.9600 |
C25—C26 | 1.382 (4) | C25'—C26' | 1.396 (4) |
C25—H25A | 0.9599 | C25'—H25B | 0.9600 |
C26—H26A | 0.9600 | C26'—H26B | 0.9600 |
C28—C33 | 1.388 (4) | C28'—C29' | 1.391 (4) |
C28—C29 | 1.391 (4) | C28'—C33' | 1.393 (4) |
C29—C30 | 1.382 (4) | C29'—C30' | 1.382 (4) |
C29—H29A | 0.9600 | C29'—H29B | 0.9600 |
C30—C31 | 1.380 (5) | C30'—C31' | 1.380 (5) |
C30—H30A | 0.9599 | C30'—H30B | 0.9601 |
C31—C32 | 1.368 (5) | C31'—C32' | 1.380 (5) |
C32—C33 | 1.397 (5) | C32'—C33' | 1.393 (4) |
C32—H32A | 0.9600 | C32'—H32B | 0.9600 |
C33—H33A | 0.9600 | C33'—H33B | 0.9599 |
| | | |
C5—O1—C1 | 120.1 (2) | C5'—O1'—C1' | 120.1 (2) |
C5—N1—C6 | 117.8 (2) | C5'—N1'—C6' | 116.8 (2) |
C5—N1—H1A | 121.2 | C5'—N1'—H1'A | 121.6 |
C6—N1—H1A | 121.0 | C6'—N1'—H1'A | 121.7 |
C7—N2—C8 | 120.8 (2) | C7'—N2'—C8' | 122.2 (2) |
C7—N2—H2D | 119.6 | C7'—N2'—H2'D | 118.9 |
C8—N2—H2D | 119.6 | C8'—N2'—H2'D | 118.8 |
C16—N3—C17 | 118.6 (2) | C16'—N3'—C17' | 118.7 (2) |
C16—N3—H3D | 120.8 | C16'—N3'—H3'D | 120.7 |
C17—N3—H3D | 120.6 | C17'—N3'—H3'D | 120.6 |
C18—N4—C19 | 119.5 (2) | C18'—N4'—C19' | 123.3 (2) |
C18—N4—H4D | 120.3 | C18'—N4'—H4'D | 118.4 |
C19—N4—H4D | 120.2 | C19'—N4'—H4'D | 118.4 |
C27—N5—C28 | 127.6 (2) | C27'—N5'—C28' | 127.6 (2) |
C27—N5—H5A | 116.1 | C27'—N5'—H5'A | 116.2 |
C28—N5—H5A | 116.3 | C28'—N5'—H5'A | 116.1 |
O8—N6—O7 | 123.2 (3) | O7'—N6'—O8' | 123.6 (3) |
O8—N6—C31 | 118.6 (3) | O7'—N6'—C31' | 118.5 (3) |
O7—N6—C31 | 118.2 (3) | O8'—N6'—C31' | 117.8 (3) |
O1—C1—C2 | 109.3 (3) | O1'—C1'—C2' | 109.1 (3) |
O1—C1—C4 | 111.0 (2) | O1'—C1'—C4' | 102.7 (2) |
C2—C1—C4 | 113.9 (3) | C2'—C1'—C4' | 111.0 (3) |
O1—C1—C3 | 102.5 (2) | O1'—C1'—C3' | 110.6 (2) |
C2—C1—C3 | 109.8 (3) | C2'—C1'—C3' | 113.2 (3) |
C4—C1—C3 | 109.8 (3) | C4'—C1'—C3' | 109.6 (3) |
C1—C2—H2A | 109.7 | C1'—C2'—H2'A | 109.4 |
C1—C2—H2B | 109.4 | C1'—C2'—H2'B | 109.7 |
H2A—C2—H2B | 109.5 | H2'A—C2'—H2'B | 109.5 |
C1—C2—H2C | 109.3 | C1'—C2'—H2'C | 109.4 |
H2A—C2—H2C | 109.5 | H2'A—C2'—H2'C | 109.5 |
H2B—C2—H2C | 109.5 | H2'B—C2'—H2'C | 109.5 |
C1—C3—H3A | 109.7 | C1'—C3'—H3'A | 109.6 |
C1—C3—H3B | 109.4 | C1'—C3'—H3'B | 109.5 |
H3A—C3—H3B | 109.5 | H3'A—C3'—H3'B | 109.5 |
C1—C3—H3C | 109.3 | C1'—C3'—H3'C | 109.3 |
H3A—C3—H3C | 109.5 | H3'A—C3'—H3'C | 109.5 |
H3B—C3—H3C | 109.5 | H3'B—C3'—H3'C | 109.5 |
C1—C4—H4A | 109.1 | C1'—C4'—H4'A | 109.4 |
C1—C4—H4B | 109.5 | C1'—C4'—H4'B | 109.4 |
H4A—C4—H4B | 109.5 | H4'A—C4'—H4'B | 109.5 |
C1—C4—H4C | 109.7 | C1'—C4'—H4'C | 109.6 |
H4A—C4—H4C | 109.5 | H4'A—C4'—H4'C | 109.5 |
H4B—C4—H4C | 109.5 | H4'B—C4'—H4'C | 109.5 |
O2—C5—N1 | 124.2 (3) | O2'—C5'—O1' | 126.1 (3) |
O2—C5—O1 | 125.2 (3) | O2'—C5'—N1' | 123.5 (3) |
N1—C5—O1 | 110.6 (2) | O1'—C5'—N1' | 110.5 (2) |
N1—C6—C7 | 109.6 (2) | N1'—C6'—C7' | 109.0 (2) |
N1—C6—H6A | 109.9 | N1'—C6'—H6'A | 109.8 |
C7—C6—H6A | 109.7 | C7'—C6'—H6'A | 109.9 |
N1—C6—H6B | 109.6 | N1'—C6'—H6'B | 110.0 |
C7—C6—H6B | 109.7 | C7'—C6'—H6'B | 109.9 |
H6A—C6—H6B | 108.2 | H6'A—C6'—H6'B | 108.3 |
O3—C7—N2 | 122.4 (2) | O3'—C7'—N2' | 122.1 (2) |
O3—C7—C6 | 122.3 (2) | O3'—C7'—C6' | 122.1 (2) |
N2—C7—C6 | 115.3 (2) | N2'—C7'—C6' | 115.8 (2) |
C9—C8—N2 | 124.1 (2) | C9'—C8'—N2' | 124.3 (2) |
C9—C8—C16 | 118.1 (2) | C9'—C8'—C16' | 117.5 (2) |
N2—C8—C16 | 117.6 (2) | N2'—C8'—C16' | 117.8 (2) |
C8—C9—C10 | 128.9 (2) | C8'—C9'—C10' | 130.2 (2) |
C8—C9—H9A | 115.5 | C8'—C9'—H9'A | 114.9 |
C10—C9—H9A | 115.5 | C10'—C9'—H9'A | 114.9 |
C11—C10—C15 | 118.4 (3) | C11'—C10'—C15' | 118.2 (3) |
C11—C10—C9 | 123.8 (2) | C11'—C10'—C9' | 123.6 (2) |
C15—C10—C9 | 117.7 (2) | C15'—C10'—C9' | 118.1 (3) |
C12—C11—C10 | 120.5 (3) | C10'—C11'—C12' | 120.9 (3) |
C12—C11—H11A | 119.8 | C10'—C11'—H11B | 119.6 |
C10—C11—H11A | 119.7 | C12'—C11'—H11B | 119.5 |
C11—C12—C13 | 120.8 (3) | C13'—C12'—C11' | 120.2 (3) |
C11—C12—H12A | 119.6 | C13'—C12'—H12B | 119.7 |
C13—C12—H12A | 119.6 | C11'—C12'—H12B | 120.0 |
C14—C13—C12 | 118.9 (3) | C14'—C13'—C12' | 119.6 (3) |
C14—C13—H13A | 120.6 | C14'—C13'—H13B | 120.2 |
C12—C13—H13A | 120.5 | C12'—C13'—H13B | 120.2 |
C13—C14—C15 | 120.7 (3) | C13'—C14'—C15' | 120.3 (3) |
C13—C14—H14A | 119.7 | C13'—C14'—H14B | 119.8 |
C15—C14—H14A | 119.6 | C15'—C14'—H14B | 120.0 |
C14—C15—C10 | 120.6 (3) | C14'—C15'—C10' | 120.7 (3) |
C14—C15—H15A | 119.7 | C14'—C15'—H15B | 119.6 |
C10—C15—H15A | 119.6 | C10'—C15'—H15B | 119.7 |
O4—C16—N3 | 120.1 (2) | O4'—C16'—N3' | 120.5 (2) |
O4—C16—C8 | 120.1 (2) | O4'—C16'—C8' | 120.5 (2) |
N3—C16—C8 | 119.7 (2) | N3'—C16'—C8' | 118.9 (2) |
N3—C17—C18 | 110.0 (2) | N3'—C17'—C18' | 109.6 (2) |
N3—C17—H17A | 109.5 | N3'—C17'—H17C | 109.9 |
C18—C17—H17A | 109.6 | C18'—C17'—H17C | 109.7 |
N3—C17—H17B | 109.8 | N3'—C17'—H17D | 109.5 |
C18—C17—H17B | 109.7 | C18'—C17'—H17D | 109.8 |
H17A—C17—H17B | 108.2 | H17C—C17'—H17D | 108.2 |
O5—C18—N4 | 121.2 (2) | O5'—C18'—N4' | 122.7 (2) |
O5—C18—C17 | 121.1 (2) | O5'—C18'—C17' | 121.8 (2) |
N4—C18—C17 | 117.7 (2) | N4'—C18'—C17' | 115.4 (2) |
N4—C19—C20 | 111.1 (2) | N4'—C19'—C20' | 112.5 (2) |
N4—C19—C27 | 113.0 (2) | N4'—C19'—C27' | 113.4 (2) |
C20—C19—C27 | 112.3 (2) | C20'—C19'—C27' | 112.1 (2) |
N4—C19—H19A | 106.7 | N4'—C19'—H19B | 106.0 |
C20—C19—H19A | 106.7 | C20'—C19'—H19B | 106.1 |
C27—C19—H19A | 106.6 | C27'—C19'—H19B | 106.1 |
C21—C20—C19 | 113.8 (2) | C21'—C20'—C19' | 110.9 (2) |
C21—C20—H20A | 108.8 | C21'—C20'—H20C | 109.5 |
C19—C20—H20A | 108.7 | C19'—C20'—H20C | 109.5 |
C21—C20—H20B | 108.8 | C21'—C20'—H20D | 109.4 |
C19—C20—H20B | 108.8 | C19'—C20'—H20D | 109.4 |
H20A—C20—H20B | 107.7 | H20C—C20'—H20D | 108.1 |
C22—C21—C26 | 117.7 (3) | C26'—C21'—C22' | 118.5 (3) |
C22—C21—C20 | 123.2 (3) | C26'—C21'—C20' | 121.2 (3) |
C26—C21—C20 | 119.0 (3) | C22'—C21'—C20' | 120.1 (2) |
C21—C22—C23 | 120.7 (3) | C21'—C22'—C23' | 120.7 (3) |
C21—C22—H22A | 119.7 | C21'—C22'—H22B | 119.7 |
C23—C22—H22A | 119.7 | C23'—C22'—H22B | 119.6 |
C24—C23—C22 | 120.7 (3) | C24'—C23'—C22' | 120.3 (3) |
C24—C23—H23A | 119.7 | C24'—C23'—H23B | 119.8 |
C22—C23—H23A | 119.6 | C22'—C23'—H23B | 119.9 |
C23—C24—C25 | 119.5 (3) | C23'—C24'—C25' | 119.8 (3) |
C23—C24—H24A | 120.3 | C23'—C24'—H24B | 120.3 |
C25—C24—H24A | 120.2 | C25'—C24'—H24B | 120.0 |
C24—C25—C26 | 119.5 (3) | C24'—C25'—C26' | 119.9 (3) |
C24—C25—H25A | 120.4 | C24'—C25'—H25B | 120.1 |
C26—C25—H25A | 120.2 | C26'—C25'—H25B | 120.0 |
C25—C26—C21 | 121.8 (3) | C21'—C26'—C25' | 120.7 (3) |
C25—C26—H26A | 119.1 | C21'—C26'—H26B | 119.8 |
C21—C26—H26A | 119.0 | C25'—C26'—H26B | 119.5 |
O6—C27—N5 | 123.8 (3) | O6'—C27'—N5' | 124.5 (3) |
O6—C27—C19 | 120.5 (3) | O6'—C27'—C19' | 120.4 (3) |
N5—C27—C19 | 115.7 (2) | N5'—C27'—C19' | 114.8 (2) |
C33—C28—C29 | 120.1 (3) | C29'—C28'—C33' | 120.3 (3) |
C33—C28—N5 | 122.1 (3) | C29'—C28'—N5' | 117.2 (2) |
C29—C28—N5 | 117.7 (2) | C33'—C28'—N5' | 122.5 (3) |
C30—C29—C28 | 120.7 (3) | C30'—C29'—C28' | 120.8 (3) |
C30—C29—H29A | 119.6 | C30'—C29'—H29B | 119.7 |
C28—C29—H29A | 119.7 | C28'—C29'—H29B | 119.5 |
C31—C30—C29 | 118.5 (3) | C31'—C30'—C29' | 118.4 (3) |
C31—C30—H30A | 120.8 | C31'—C30'—H30B | 120.8 |
C29—C30—H30A | 120.7 | C29'—C30'—H30B | 120.8 |
C32—C31—C30 | 121.9 (3) | C32'—C31'—C30' | 122.0 (3) |
C32—C31—N6 | 119.4 (3) | C32'—C31'—N6' | 119.5 (3) |
C30—C31—N6 | 118.6 (3) | C30'—C31'—N6' | 118.5 (3) |
C31—C32—C33 | 119.7 (3) | C31'—C32'—C33' | 119.6 (3) |
C31—C32—H32A | 120.2 | C31'—C32'—H32B | 120.1 |
C33—C32—H32A | 120.1 | C33'—C32'—H32B | 120.2 |
C28—C33—C32 | 119.1 (3) | C32'—C33'—C28' | 118.9 (3) |
C28—C33—H33A | 120.4 | C32'—C33'—H33B | 120.4 |
C32—C33—H33A | 120.5 | C28'—C33'—H33B | 120.7 |
| | | |
C5—O1—C1—C2 | 69.0 (3) | C5'—O1'—C1'—C2' | −70.8 (3) |
C5—O1—C1—C4 | −57.4 (4) | C5'—O1'—C1'—C4' | 171.3 (3) |
C5—O1—C1—C3 | −174.5 (3) | C5'—O1'—C1'—C3' | 54.4 (4) |
C6—N1—C5—O2 | 10.3 (4) | C1'—O1'—C5'—O2' | 3.2 (4) |
C6—N1—C5—O1 | −169.8 (2) | C1'—O1'—C5'—N1' | −176.1 (2) |
C1—O1—C5—O2 | 0.8 (4) | C6'—N1'—C5'—O2' | −15.4 (4) |
C1—O1—C5—N1 | −179.1 (2) | C6'—N1'—C5'—O1' | 164.0 (2) |
C5—N1—C6—C7 | 53.9 (3) | C5'—N1'—C6'—C7' | −52.7 (3) |
C8—N2—C7—O3 | −1.3 (4) | C8'—N2'—C7'—O3' | 0.7 (4) |
C8—N2—C7—C6 | 177.4 (2) | C8'—N2'—C7'—C6' | −178.3 (2) |
N1—C6—C7—O3 | 35.0 (4) | N1'—C6'—C7'—O3' | −29.7 (4) |
N1—C6—C7—N2 | −143.8 (2) | N1'—C6'—C7'—N2' | 149.3 (2) |
C7—N2—C8—C9 | 126.8 (3) | C7'—N2'—C8'—C9' | −137.9 (3) |
C7—N2—C8—C16 | −59.3 (3) | C7'—N2'—C8'—C16' | 49.9 (3) |
N2—C8—C9—C10 | −7.6 (5) | N2'—C8'—C9'—C10' | 9.2 (5) |
C16—C8—C9—C10 | 178.5 (2) | C16'—C8'—C9'—C10' | −178.6 (3) |
C8—C9—C10—C11 | −27.8 (5) | C8'—C9'—C10'—C11' | 29.5 (5) |
C8—C9—C10—C15 | 155.1 (3) | C8'—C9'—C10'—C15' | −154.2 (3) |
C15—C10—C11—C12 | 0.8 (4) | C15'—C10'—C11'—C12' | −1.0 (4) |
C9—C10—C11—C12 | −176.3 (3) | C9'—C10'—C11'—C12' | 175.3 (3) |
C10—C11—C12—C13 | −2.0 (5) | C10'—C11'—C12'—C13' | 1.8 (5) |
C11—C12—C13—C14 | 1.0 (5) | C11'—C12'—C13'—C14' | −0.2 (5) |
C12—C13—C14—C15 | 1.3 (5) | C12'—C13'—C14'—C15' | −2.1 (5) |
C13—C14—C15—C10 | −2.5 (5) | C13'—C14'—C15'—C10' | 2.8 (5) |
C11—C10—C15—C14 | 1.5 (4) | C11'—C10'—C15'—C14' | −1.2 (4) |
C9—C10—C15—C14 | 178.7 (3) | C9'—C10'—C15'—C14' | −177.8 (3) |
C17—N3—C16—O4 | −0.9 (4) | C17'—N3'—C16'—O4' | 0.6 (4) |
C17—N3—C16—C8 | −178.0 (2) | C17'—N3'—C16'—C8' | 175.6 (2) |
C9—C8—C16—O4 | −22.0 (4) | C9'—C8'—C16'—O4' | 31.3 (4) |
N2—C8—C16—O4 | 163.7 (2) | N2'—C8'—C16'—O4' | −156.0 (2) |
C9—C8—C16—N3 | 155.2 (3) | C9'—C8'—C16'—N3' | −143.7 (3) |
N2—C8—C16—N3 | −19.2 (3) | N2'—C8'—C16'—N3' | 29.0 (3) |
C16—N3—C17—C18 | 55.1 (3) | C16'—N3'—C17'—C18' | −55.5 (3) |
C19—N4—C18—O5 | 2.8 (4) | C19'—N4'—C18'—O5' | −6.1 (4) |
C19—N4—C18—C17 | −175.9 (2) | C19'—N4'—C18'—C17' | 173.9 (2) |
N3—C17—C18—O5 | 46.3 (3) | N3'—C17'—C18'—O5' | −49.9 (3) |
N3—C17—C18—N4 | −135.0 (2) | N3'—C17'—C18'—N4' | 130.1 (2) |
C18—N4—C19—C20 | 141.4 (2) | C18'—N4'—C19'—C20' | −67.0 (3) |
C18—N4—C19—C27 | −91.3 (3) | C18'—N4'—C19'—C27' | 61.4 (3) |
N4—C19—C20—C21 | −47.5 (3) | N4'—C19'—C20'—C21' | −53.9 (3) |
C27—C19—C20—C21 | −175.2 (2) | C27'—C19'—C20'—C21' | 177.0 (2) |
C19—C20—C21—C22 | −35.2 (4) | C19'—C20'—C21'—C26' | −89.0 (3) |
C19—C20—C21—C26 | 142.3 (3) | C19'—C20'—C21'—C22' | 87.0 (3) |
C26—C21—C22—C23 | −1.8 (5) | C26'—C21'—C22'—C23' | 1.5 (5) |
C20—C21—C22—C23 | 175.7 (3) | C20'—C21'—C22'—C23' | −174.6 (3) |
C21—C22—C23—C24 | −0.1 (6) | C21'—C22'—C23'—C24' | −1.1 (5) |
C22—C23—C24—C25 | 1.9 (6) | C22'—C23'—C24'—C25' | −0.4 (5) |
C23—C24—C25—C26 | −1.8 (5) | C23'—C24'—C25'—C26' | 1.3 (5) |
C24—C25—C26—C21 | −0.2 (5) | C22'—C21'—C26'—C25' | −0.6 (5) |
C22—C21—C26—C25 | 2.0 (5) | C20'—C21'—C26'—C25' | 175.5 (3) |
C20—C21—C26—C25 | −175.6 (3) | C24'—C25'—C26'—C21' | −0.8 (5) |
C28—N5—C27—O6 | −9.2 (5) | C28'—N5'—C27'—O6' | 0.1 (5) |
C28—N5—C27—C19 | 168.2 (2) | C28'—N5'—C27'—C19' | 175.0 (2) |
N4—C19—C27—O6 | −165.7 (2) | N4'—C19'—C27'—O6' | −164.2 (3) |
C20—C19—C27—O6 | −39.1 (3) | C20'—C19'—C27'—O6' | −35.5 (3) |
N4—C19—C27—N5 | 16.8 (3) | N4'—C19'—C27'—N5' | 20.7 (3) |
C20—C19—C27—N5 | 143.4 (2) | C20'—C19'—C27'—N5' | 149.3 (2) |
C27—N5—C28—C33 | −23.1 (4) | C27'—N5'—C28'—C29' | −157.5 (3) |
C27—N5—C28—C29 | 160.2 (3) | C27'—N5'—C28'—C33' | 23.2 (4) |
C33—C28—C29—C30 | −0.2 (4) | C33'—C28'—C29'—C30' | −0.4 (4) |
N5—C28—C29—C30 | 176.6 (3) | N5'—C28'—C29'—C30' | −179.7 (3) |
C28—C29—C30—C31 | −0.3 (4) | C28'—C29'—C30'—C31' | −0.2 (4) |
C29—C30—C31—C32 | 1.3 (5) | C29'—C30'—C31'—C32' | 0.7 (5) |
C29—C30—C31—N6 | −178.6 (3) | C29'—C30'—C31'—N6' | 180.0 (3) |
O8—N6—C31—C32 | 2.4 (5) | O7'—N6'—C31'—C32' | 176.2 (3) |
O7—N6—C31—C32 | −177.5 (4) | O8'—N6'—C31'—C32' | −3.2 (5) |
O8—N6—C31—C30 | −177.7 (4) | O7'—N6'—C31'—C30' | −3.1 (5) |
O7—N6—C31—C30 | 2.4 (5) | O8'—N6'—C31'—C30' | 177.5 (3) |
C30—C31—C32—C33 | −1.7 (5) | C30'—C31'—C32'—C33' | −0.5 (5) |
N6—C31—C32—C33 | 178.2 (3) | N6'—C31'—C32'—C33' | −179.8 (3) |
C29—C28—C33—C32 | −0.1 (5) | C31'—C32'—C33'—C28' | −0.2 (5) |
N5—C28—C33—C32 | −176.8 (3) | C29'—C28'—C33'—C32' | 0.6 (4) |
C31—C32—C33—C28 | 1.0 (5) | N5'—C28'—C33'—C32' | 179.9 (3) |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1A···O3′i | 0.90 | 2.06 | 2.898 (3) | 154 |
N2—H2D···O5′ii | 0.90 | 2.04 | 2.879 (3) | 156 |
N3—H3D···O2 | 0.90 | 2.27 | 3.053 (3) | 145 |
N4—H4D···O4′iii | 0.90 | 2.06 | 2.917 (3) | 160 |
N5—H5A···O4 | 0.90 | 2.09 | 2.917 (3) | 153 |
N5—H5A···N4 | 0.90 | 2.26 | 2.724 (3) | 112 |
N1′—H1′A···O3iv | 0.90 | 2.16 | 2.965 (3) | 149 |
N2′—H2′D···O5v | 0.90 | 1.83 | 2.693 (3) | 159 |
N3′—H3′D···O2′ | 0.90 | 2.46 | 3.215 (3) | 141 |
N4′—H4′D···O4vi | 0.90 | 2.05 | 2.873 (3) | 151 |
N5′—H5′A···O4′ | 0.90 | 2.13 | 2.964 (3) | 153 |
N5′—H5′A···N4′ | 0.90 | 2.28 | 2.737 (3) | 111 |
Symmetry codes: (i) x, y, z+1; (ii) x, y−1, z+1; (iii) x+1, y−1, z+1; (iv) x, y, z−1; (v) x, y+1, z−1; (vi) x−1, y+1, z−1. |
Experimental details
Crystal data |
Chemical formula | C33H36N6O8 |
Mr | 644.68 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 105 |
a, b, c (Å) | 10.328 (2), 11.605 (2), 14.796 (3) |
α, β, γ (°) | 70.00 (3), 86.37 (3), 76.19 (3) |
V (Å3) | 1617.9 (5) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 0.10 |
Crystal size (mm) | 0.5 × 0.4 × 0.3 |
|
Data collection |
Diffractometer | KUMA KM–4 diffractometer |
Absorption correction | – |
No. of measured, independent and observed [I > 2σ(I)] reflections | 11299, 5804, 5429 |
Rint | 0.029 |
(sin θ/λ)max (Å−1) | 0.618 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.032, 0.105, 1.02 |
No. of reflections | 5804 |
No. of parameters | 847 |
No. of restraints | 3 |
H-atom treatment | H-atom parameters constrained |
Δρmax, Δρmin (e Å−3) | 0.27, −0.37 |
Absolute structure | Flack (1983) |
Selected geometric parameters (Å, º) topN2—C8 | 1.421 (3) | N2'—C8' | 1.413 (3) |
N4—C19 | 1.454 (3) | N4'—C19' | 1.454 (3) |
C8—C9 | 1.339 (4) | C8'—C9' | 1.339 (4) |
C8—C16 | 1.489 (4) | C8'—C16' | 1.488 (4) |
C19—C20 | 1.529 (4) | C19'—C20' | 1.531 (4) |
C19—C27 | 1.537 (4) | C19'—C27' | 1.543 (4) |
| | | |
C9—C8—N2 | 124.1 (2) | C9'—C8'—N2' | 124.3 (2) |
C9—C8—C16 | 118.1 (2) | C9'—C8'—C16' | 117.5 (2) |
N2—C8—C16 | 117.6 (2) | N2'—C8'—C16' | 117.8 (2) |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
N1—H1A···O3'i | 0.90 | 2.06 | 2.898 (3) | 154.4 |
N2—H2D···O5'ii | 0.90 | 2.04 | 2.879 (3) | 155.5 |
N3—H3D···O2 | 0.90 | 2.27 | 3.053 (3) | 145.2 |
N4—H4D···O4'iii | 0.90 | 2.06 | 2.917 (3) | 159.5 |
N5—H5A···O4 | 0.90 | 2.09 | 2.917 (3) | 152.8 |
N5—H5A···N4 | 0.90 | 2.26 | 2.724 (3) | 111.6 |
N1'—H1'A···O3iv | 0.90 | 2.16 | 2.965 (3) | 149.2 |
N2'—H2'D···O5v | 0.90 | 1.83 | 2.693 (3) | 158.9 |
N3'—H3'D···O2' | 0.90 | 2.46 | 3.215 (3) | 141.1 |
N4'—H4'D···O4vi | 0.90 | 2.05 | 2.873 (3) | 151.3 |
N5'—H5'A···O4' | 0.90 | 2.13 | 2.964 (3) | 153.2 |
N5'—H5'A···N4' | 0.90 | 2.28 | 2.737 (3) | 111.2 |
Symmetry codes: (i) x, y, z+1; (ii) x, y−1, z+1; (iii) x+1, y−1, z+1; (iv) x, y, z−1; (v) x, y+1, z−1; (vi) x−1, y+1, z−1. |
Important torsional angles. topAngle | A | B |
Φ0 C6-N1-C5-O1 | -169.8 (2) | 164.0 (2) |
ω0 C1-O1-C5-N1 | -179.1 (2) | -176.1 (2) |
Φ1 C5-N1-C6-C7 | 53.9 (3) | -52.7 (3) |
ω1 C8-N2-C7-C6 | 177.4 (2) | -178.3 (2) |
Ψ1 N1-C6-C7-N2 | -143.8 (2) | 149.3 (2) |
Φ2 C7-N2-C8-C16 | -59.3 (3) | 49.9 (3) |
χ1 N2-C8-C9-C10 | -7.6 (4) | 9.2 (5) |
χ2,1 C8-C9-C10-C11 | -27.8 (4) | 29.5 (5) |
χ2,2 C8-C9-C10-C15 | 155.1 (2) | -154.2 (3) |
ω2 C17-N3-C16-C8 | -178.0 (2) | 175.3 (3) |
Ψ2 N2-C8-C16-N3 | -19.2 (3) | 29.0 (3) |
Φ3 C16-N3-C17-C18 | 55.1 (2) | -55.6 (3) |
ω3 C19-N4-C18-C17 | -175.9 (2) | 173.9 (2) |
Ψ3 N3-C17-C18-N4 | -135.0 (2) | 130.1 (2) |
Φ4 C18-N4-C19-C27 | -91.3 (2) | 61.4 (3) |
ω4 C28-N5-C27-C19 | 168.2 (2) | 175.0 (2) |
Ψ4 N4-C19-C27-N5 | 16.8 (3) | 20.7 (3) |
The α, β–dehydroaminoacid residues have been found to occur naturally in several microbial peptides and antibiotics (Noda et al., 1983; Spatola, 1983). Their presence in peptides confers increased resistance to enzymatic degradation and for this reason many highly active analogues of bioactive peptides have been designed and synthesized (Fisher et al., 1981; Costa et al., 1983; Sharma & Chauhan, 1988). In particular, α,β–dehydrophenylalanine (ΔPhe) residues exhibit preferential secondary structural features both in the solid state and in solution. Determination of the crystal and molecular structure of many ΔPhe containing peptides has provided evidence that ΔPhe is strong inducer of β–bends (Venkatachalam, 1968) in short sequences with single ΔPhe residue (Główka et al., 1987; Główka, 1988; Aubry et al., 1991) and of 310–helical structures in long sequences (Rajashankar et al., 1992; Padmanabhan & Singh, 1993; Rajashankar, Ramakumar, Jain & Chauhan et al., 1995; Rajashankar, Ramakumar, Mal et al., 1995; Jain, 1997). Additionally, the final conformation of any ΔPhe peptide depends upon the number and position of ΔPhe residues as well as the nature of the amino acids flanking them (Rajashankar et al., 1996).
Here we present the crystal structure of a tetrapeptide containing one ΔZPhe between two flexible glycine residues and one phenylalanine, Boc0–Gly1–ΔPhe2–Gly3–Phe4–p–NA (p–NA is para–nitroaniline), (I). In the independent part of the unit cell there are two independent molecules (A and B) differing in conformation (Fig. 1). The bond lengths and bond angles for both molecules are the same within 5 σ, and selected parameters there are in Table 1. \sch
The Cα═Cβ (C8—C9 and C8'—C9') distances for the ΔPhe in A and B agree well with the standard double bond distance observed in the structures containing ΔPhe residues (e.g. Główka, 1988). The conjugation of the aromatic ring with the Cα═Cβ bond is extended to the N—Cα (N2—C8 and N2'—C8') and Cα—C (C8—C16 and C8'—C16') bonds. It leads to the shortening of about 0.35 Å for N—Cα and 0.55 Å for Cα—C bonds in respect to the corresponding bonds in saturated Phe4 unit (N4—C19, N4'—C19', C19—C27 and C19'—C27'). The steric contacts between the side-chain and main-chain atoms of the ΔPhe residue are partly relaxed by rearrangement of bond angles at Cα and Cβ atoms. For example, the N—Cα═Cβ (N2—C8—C9 and N2'—C8'—C9') angles are increased from the value of 120°, ca 4°, whereas the Cβ═Cα—C (C9—C8—C16 and C9'—C8'—C16') angles are reduced of ca 2°. Similar effects are observed in Boc–Val–ΔPhe–ΔPhe–ΔPhe–Val–OMe (Jain, 1997).
All the amino acids in the peptide are linked trans to each other with the deviation of ω from 180° of less than ca 6° [with the exception of 11.8 (2)° for ω4 for the A molecule]. The torsion angles in the main chains of both molecules and the (Φ/Ψ) of Gly1 and ΔZPhe2 approximate the values assigned to the amino acid residues in the corners of a type II β–turn. The intramolecular hydrogen bonds between the amide (N3 and N3') of Gly3 and the carboxyl (O2 and O2') of the Boc groups are similar to those observed in Boc–Gly–ΔPhe–Gly–OMe (Główka, 1988). The torsion angles χ1 [-7.4 (4) and 9.2 (4)°], χ2,1 [-27.9 (4) and 29.5 (4)°] and χ2,2 [155.0 (2) and -154.1 (2)°] of the ΔPhe suggest that the side chains in A and B molecules are planar.
The two Gly residues adopt a conformation known as a polyglycine helix (Walton, 1981) with Φ and Ψ close to 80 and -150°. The relative inclination of the planes of two Gly units are 37.5 (3)° for A and 31.5 (3)° for B. The torsion angles for the Boc group ω0 and Φ0 in both molecules (A and B) correspond to a trans–trans conformation. This makes it possible for O2 (Boc) atoms to take part in the intramolecular N3—H3D···O2 hydrogen bond (Table 2). The carbonyl oxygen of ΔPhe2 takes part in another intramolecular hydrogen bond with the amide group of p–NA. Those two intramolecular hydrogen bonds stabilize the conformation of both molecules. Each of the molecules is connected to three others by N—H···O hydrogen bonds of medium strength.