Acta Crystallographica Section F

Structural Biology and Crystallization Communications

Volume 63, Part 10 (October 2007)

crystallization communications

Acta Cryst. (2007). F63, 839-843 [ doi:10.1107/S1744309107040857 ]

Cocrystallizing natural RNA with its unnatural mirror image: biochemical and preliminary X-ray diffraction analysis of a 5S rRNA A-helix racemate

C. Förster, A. B. E. Brauer, D. Lehmann, T. Borowski, S. Brode, J. P. Fürste, M. Perbandt, C. Betzel and V. A. Erdmann

Abstract: Chemically synthesized RNAs with the unnatural L-configuration possess enhanced in vivo stability and nuclease resistance, which is a highly desirable property for pharmacological applications. For a structural comparison, both L- and D-RNA oligonucleotides of a shortened Thermus flavus 5S rRNA A-helix were chemically synthesized. The enantiomeric RNA duplexes were stochiometrically cocrystallized as a racemate, which enabled analysis of the D- and L-RNA enantiomers in the same crystals. In addition to a biochemical investigation, diffraction data were collected to 3.0 Å resolution using synchrotron radiation. The crystals belonged to space group P3₁21, with unit-cell parameters a = b = 35.59, c = 135.30 Å, [gamma] = 120° and two molecules per asymmetric unit.

Keywords: 5S rRNA; oligonucleotides; RNA racemates; spiegelmers; D- and L-RNA enantiomers; microhelices.