1lnt

From Proteopedia

Revision as of 10:32, 20 March 2008

Crystal Structure of the Highly Conserved RNA Internal Loop of SRP

Overview

The crystal structure of an RNA dodecamer, r(GCGUCAGGUC(Br)CG)/r(CGGAAGCAG(Br)CGC), containing a fragment from the signal recognition particle (SRP) RNA (domain IV) of Escherichia coli, has been determined at 1.7 A resolution with 21 666 independent reflections and an R(work) and R(free) of 20.1 and 22.5%, respectively. The structure exhibits a novel crystal packing pattern for RNA oligomer duplexes: one end of the duplex adopts the stacking interaction, while the other end adopts the abutting interaction in the minor groove. The symmetric loop of the SRP, r(CAGG)/r(AGCA), in the center of the dodecamer forms two different conformations of the A.C mismatch, a sheared G.G and a symmetrical G.A mismatch. These four mismatches present a unique surface for the abutting interaction. The involvement of the two A.C mismatches in the abutting interaction implies that these mismatches are the important sites for interaction with proteins. The conformation of the symmetric loop is greatly stabilized by hydrated metal ions, which display flexibility in adjusting their geometry and coordination in interaction with nucleic acids. Comparison with other crystal structures of fragments of 4.5S RNA indicates that the conformation of the symmetric loop is independent of the asymmetrical loop in domain IV.

About this Structure

1LNT is a Protein complex structure of sequences from [1]. Full crystallographic information is available from OCA.

Reference

Structure of an RNA dodecamer containing a fragment from SRP domain IV of Escherichia coli., Deng J, Xiong Y, Pan B, Sundaralingam M, Acta Crystallogr D Biol Crystallogr. 2003 Jun;59(Pt 6):1004-11. Epub 2003, May 23. PMID:12777762

Page seeded by OCA on Thu Mar 20 12:32:57 2008