ISSN:
1399-0047
Source:
Crystallography Journals Online : IUCR Backfile Archive 1948-2001
Topics:
Chemistry and Pharmacology
,
Geosciences
,
Physics
Notes:
An RNA helix with seven base pairs which was derived from the acceptor stem of Escherichia coli tRNAAla, rGGGGCUA·rUAGCUCC (ALAwt), as well as a variant, rGGGGCUA·rUAGCCCC (ALAC70), in which the single G·U wobble base pair of ALAwt was replaced by G·C, crystallize in space group C2. Both non-isomorphic crystal forms display a complex packing pattern, which can be described alternatively as disorder or pseudo-merohedral twinning. The structure of ALAwt was determined by SIRAS phasing using an isomorphous iodine derivative, rGGGGCi5UA·rUAGCUCC (ALAI). All three RNA structures were subsequently subjected to twin refinement in space group P1, using anisotropic thermal displacement parameters at resolutions of 1.16, 1.23 and 1.4 Å for ALAwt, ALAI and ALAC70, respectively. Alternatively, the structure of ALAwt was refined in space group C2 assuming twofold disorder of the molecular orientation. The refined structures are of reasonable quality according to all available indicators. There are no systematic differences between the molecular models resulting from twin refinement and disorder refinement.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1107/S0907444999007441
