2c4z

From Proteopedia

Revision as of 14:10, 20 March 2008

MS2-RNA HAIRPIN (2SU-5-6) COMPLEX

Overview

We have determined the X-ray structures of six MS2 RNA hairpin-coat-protein complexes having five different substitutions at the hairpin loop base -5. This is a uracil in the wild-type hairpin and contacts the coat protein both by stacking on to a tyrosine side chain and by hydrogen bonding to an asparagine side chain. The RNA consensus sequence derived from coat protein binding studies with natural sequence variants suggested that the -5 base needs to be a pyrimidine for strong binding. The five -5 substituents used in this study were 5-bromouracil, pyrimidin-2-one, 2-thiouracil, adenine, and guanine. The structure of the 5-bromouracil complex was determined to 2.2 A resolution, which is the highest to date for any MS2 RNA-protein complex. All the complexes presented here show very similar conformations, despite variation in affinity in solution. The results suggest that the stacking of the -5 base on to the tyrosine side chain is the most important driving force for complex formation. A number of hydrogen bonds that are present in the wild-type complex are not crucial for binding, as they are missing in one or more of the complexes. The results also reveal the flexibility of this RNA-protein interface, with respect to functional group variation, and may be generally applicable to other RNA-protein complexes.

About this Structure

2C4Z is a Single protein structure of sequence from Enterobacterio phage ms2. This structure supersedes the now removed PDB entry 1HDW. Full crystallographic information is available from OCA.

Reference

Structural basis of pyrimidine specificity in the MS2 RNA hairpin-coat-protein complex., Grahn E, Moss T, Helgstrand C, Fridborg K, Sundaram M, Tars K, Lago H, Stonehouse NJ, Davis DR, Stockley PG, Liljas L, RNA. 2001 Nov;7(11):1616-27. PMID:11720290

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