4L81

Structure of the SAM-I/IV riboswitch (env87(deltaU92, deltaG93))

4L81 の概要

• エントリーDOI: 10.2210/pdb4l81/pdb
• 分子名称: SAM-I/IV variant riboswitch aptamer domain, S-ADENOSYLMETHIONINE, COBALT HEXAMMINE(III), ... (4 entities in total)
• 機能のキーワード: riboswitch, gene regulation, sam binding, rna
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 33248.09

構造登録者

Trausch, J.J.,Reyes, F.E.,Edwards, A.L.,Batey, R.T. (登録日: 2013-06-15, 公開日: 2014-05-28, 最終更新日: 2023-09-20)

主引用文献

Trausch, J.J.,Xu, Z.,Edwards, A.L.,Reyes, F.E.,Ross, P.E.,Knight, R.,Batey, R.T.
Structural basis for diversity in the SAM clan of riboswitches.
Proc.Natl.Acad.Sci.USA, 111:6624-6629, 2014

PubMed Abstract: In bacteria, sulfur metabolism is regulated in part by seven known families of riboswitches that bind S-adenosyl-l-methionine (SAM). Direct binding of SAM to these mRNA regulatory elements governs a downstream secondary structural switch that communicates with the transcriptional and/or translational expression machinery. The most widely distributed SAM-binding riboswitches belong to the SAM clan, comprising three families that share a common SAM-binding core but differ radically in their peripheral architecture. Although the structure of the SAM-I member of this clan has been extensively studied, how the alternative peripheral architecture of the other families supports the common SAM-binding core remains unknown. We have therefore solved the X-ray structure of a member of the SAM-I/IV family containing the alternative "PK-2" subdomain shared with the SAM-IV family. This structure reveals that this subdomain forms extensive interactions with the helix housing the SAM-binding pocket, including a highly unusual mode of helix packing in which two helices pack in a perpendicular fashion. Biochemical and genetic analysis of this RNA reveals that SAM binding induces many of these interactions, including stabilization of a pseudoknot that is part of the regulatory switch. Despite strong structural similarity between the cores of SAM-I and SAM-I/IV members, a phylogenetic analysis of sequences does not indicate that they derive from a common ancestor.

PubMed: 24753586
DOI: 10.1073/pnas.1312918111

実験手法

X-RAY DIFFRACTION (2.95 Å)