Acta Crystallographica Section B

Structural Science

Volume 52, Part 5 (October 1996)

research papers

Acta Cryst. (1996). B52, 865-875 [ doi:10.1107/S0108768196005241 ]

Structure of tris(cyclohexylammonium) phosphoenolpyruvate monohydrate and crystal chemistry of phosphoenolpyruvates

M. Souhassou, P. M. Schaber and R. H. Blessing

Abstract: The crystal structure of (C₆H₁₁NH₃⁺)₃.Pep^3-.H₂O, where Pep^3- = (O^-)₂P(O)-O-C(CH₂)-CO^-₂, is reported and the systematic structural variations among 19 crystallographic occurrences of H₃Pep, H₂Pep^-, HPep^2- and Pep^3- species, which are important phosphate donors in the ATP cycle of bioenergetics, are reviewed. Tris(cyclohexylammonium) phosphoenolpyruvate monohydrate, (C₆H₁₁NH₃⁺)₃.[O₃POC(CH₂)CO₂]^3-.H₂O, M_r = 483.6, m.p. 418-420 K; T = 296 (1) K; orthorhombic, P2₁2₁2₁; a = 16.7042 (5), b = 24.4881 (6), c = 6.38910 (10) Å; V = 2613.49 (11) Å³, Z = 4, D_x = 1.23, D_m = 1.22 mg mm^-3, = 0.14 mm^-1 for (MoK [alpha] ) = 0.7107 Å; F = 1056 e; R(|F|) = 0.0608 for 6056 hkl and hk $\bar l$ data with (sin )/ [less-than or equal to] 0.65 Å^-1.