3IVN

Structure of the U65C mutant A-riboswitch aptamer from the Bacillus subtilis pbuE operon

3IVN の概要

• エントリーDOI: 10.2210/pdb3ivn/pdb
• 分子名称: A-riboswitch, MAGNESIUM ION, BROMIDE ION, ... (4 entities in total)
• 機能のキーワード: aptamer, rna, a-riboswitch
• 由来する生物種: Bacillus subtilis
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 45527.22

構造登録者

Delfosse, V.,Dagenais, P.,Chausse, D.,Di Tomasso, G.,Legault, P. (登録日: 2009-09-01, 公開日: 2010-01-19, 最終更新日: 2023-09-06)

主引用文献

Delfosse, V.,Bouchard, P.,Bonneau, E.,Dagenais, P.,Lemay, J.F.,Lafontaine, D.A.,Legault, P.
Riboswitch structure: an internal residue mimicking the purine ligand.
Nucleic Acids Res., 38:2057-2068, 2010

PubMed Abstract: The adenine and guanine riboswitches regulate gene expression in response to their purine ligand. X-ray structures of the aptamer moiety of these riboswitches are characterized by a compact fold in which the ligand forms a Watson-Crick base pair with residue 65. Phylogenetic analyses revealed a strict restriction at position 39 of the aptamer that prevents the G39-C65 and A39-U65 combinations, and mutational studies indicate that aptamers with these sequence combinations are impaired for ligand binding. In order to investigate the rationale for sequence conservation at residue 39, structural characterization of the U65C mutant from Bacillus subtilis pbuE adenine riboswitch aptamer was undertaken. NMR spectroscopy and X-ray crystallography studies demonstrate that the U65C mutant adopts a compact ligand-free structure, in which G39 occupies the ligand-binding site of purine riboswitch aptamers. These studies present a remarkable example of a mutant RNA aptamer that adopts a native-like fold by means of ligand mimicking and explain why this mutant is impaired for ligand binding. Furthermore, this work provides a specific insight into how the natural sequence has evolved through selection of nucleotide identities that contribute to formation of the ligand-bound state, but ensures that the ligand-free state remains in an active conformation.

PubMed: 20022916
DOI: 10.1093/nar/gkp1080

実験手法

X-RAY DIFFRACTION (2.8 Å)