2FMX

An open conformation of switch I revealed by Sar1-GDP crystal structure at low Mg(2+)

2FMX の概要

• エントリーDOI: 10.2210/pdb2fmx/pdb
• 関連するPDBエントリー: 1F6B 2FA9
• 分子名称: GTP-binding protein SAR1b, SULFATE ION, GUANOSINE-5'-DIPHOSPHATE, ... (5 entities in total)
• 機能のキーワード: sar1, cop ii assembly, dimerization, protein transport
• 由来する生物種: Cricetulus griseus (Chinese hamster)
• 細胞内の位置: Endoplasmic reticulum membrane; Peripheral membrane protein: Q9QVY3
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 45225.50

構造登録者

Rao, Y.,Bian, C.,Yuan, C.,Li, Y.,Huang, M. (登録日: 2006-01-10, 公開日: 2006-09-05, 最終更新日: 2024-03-13)

主引用文献

Rao, Y.,Bian, C.,Yuan, C.,Li, Y.,Chen, L.,Ye, X.,Huang, Z.,Huang, M.
An open conformation of switch I revealed by Sar1-GDP crystal structure at low Mg(2+)
Biochem.Biophys.Res.Commun., 348:908-915, 2006

PubMed Abstract: Mg2+ is essential for guanosine triphosphatase activity and plays key roles in guanine nucleotide binding and preserving the structural integrity of GTP-binding proteins. To understand the structural basis for Mg2+ function during the GDP/GTP exchange process, we determined the crystal structure of Delta9-Sar1-GDP at low Mg2+ concentration at 1.8A. Two Sar1-GDP molecules in the crystal form a dimer with Mg2+ presenting only in molecule B but not in molecule A. The absence of Mg2+ induces significant conformational changes in the switch I region in molecule A that shows similarities with those of Ha-Ras bound to Sos. The current structure reveals an important regulatory role for Mg2+. We suggest that guanine nucleotide exchange factor may utilize this feature to generate an open conformation for GDP/GTP exchange. Furthermore, we propose a mechanism for COPII assembly and disassembly in which dimerization of Sar1 plays an important role.

PubMed: 16899220
DOI: 10.1016/j.bbrc.2006.07.148

実験手法

X-RAY DIFFRACTION (1.82 Å)