1DQH

CRYSTAL STRUCTURE OF HELIX II OF THE X. LAEVIS SOMATIC 5S RRNA WITH A CYTOSINE BULGE IN TWO CONFORMATIONS

1DQH の概要

• エントリーDOI: 10.2210/pdb1dqh/pdb
• 関連するPDBエントリー: 1DQF
• 分子名称: RNA (5'-R(*GP*CP*CP*AP*CP*CP*CP*UP*G)-3'), RNA (5'-R(*CP*AP*GP*GP*GP*UP*CP*GP*GP*C)-3') (3 entities in total)
• 機能のキーワード: double helix, cytosine bulge, rna
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 6038.72

構造登録者

Xiong, Y.,Sundaralingam, M. (登録日: 2000-01-04, 公開日: 2000-11-13, 最終更新日: 2024-02-07)

主引用文献

Xiong, Y.,Sundaralingam, M.
Two crystal forms of helix II of Xenopus laevis 5S rRNA with a cytosine bulge.
RNA, 6:1316-1324, 2000

PubMed Abstract: The crystal structure of r(GCCACCCUG).r(CAGGGUCGGC), helix II of the Xenopus laevis 5S rRNA with a cytosine bulge (underlined), has been determined in two forms at 2.2 A (Form I, space group P4(2)2(1)2, a = b = 57.15 A and c = 43.54 A) and 1.7 A (Form II, space group P4(3)2(1)2, a = b = 32.78 A and c = 102.5 A). The helical regions of the nonamers are found in the standard A-RNA conformations and the two forms have an RMS deviation of 0.75 A. However, the cytosine bulge adopts two significantly different conformations with an RMS deviation of 3.9 A. In Form I, the cytosine bulge forms an intermolecular C+*G.C triple in the major groove of a symmetry-related duplex with intermolecular hydrogen bonds between N4C and O6G, and between protonated N3+C and N7G. In contrast, a minor groove C*G.C triple is formed in Form II with intermolecular hydrogen bonds between O2C and N2G, and between N3C and N3G with a water bridge. A partial major groove opening was observed in Form I structure at the bulge site. Two Ca2+ ions were found in Form I helix whereas there were none in Form II. The structural comparison of these two forms indicates that bulged residues can adopt a variety of conformations with little perturbation to the global helix structure. This suggests that bulged residues could function as flexible latches in bridging double helical motifs and facilitate the folding of large RNA molecules.

PubMed: 10999608
DOI: 10.1017/S135583820000090X

実験手法

X-RAY DIFFRACTION (1.7 Å)