4NON

Crystal structure of GDP-bound A143S mutant of the S. thermophilus FeoB G-domain

4NON の概要

• エントリーDOI: 10.2210/pdb4non/pdb
• 関連するPDBエントリー: 3LX8
• 分子名称: Ferrous iron uptake transporter protein B, GUANOSINE-5'-DIPHOSPHATE (3 entities in total)
• 機能のキーワード: g protein, iron transport, gtpase, transmembrane, metal transport, gtp binding
• 由来する生物種: Streptococcus thermophilus
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 58804.06

構造登録者

Guilfoyle, A.P.,Deshpande, C.N.,Jormakka, M. (登録日: 2013-11-20, 公開日: 2014-04-02, 最終更新日: 2024-02-28)

主引用文献

Guilfoyle, A.P.,Deshpande, C.N.,Vincent, K.,Pedroso, M.M.,Schenk, G.,Maher, M.J.,Jormakka, M.
Structural and functional analysis of a FeoB A143S G5 loop mutant explains the accelerated GDP release rate.
Febs J., 281:2254-2265, 2014

PubMed Abstract: GTPases (G proteins) hydrolyze the conversion of GTP to GDP and free phosphate, comprising an integral part of prokaryotic and eukaryotic signaling, protein biosynthesis and cell division, as well as membrane transport processes. The G protein cycle is brought to a halt after GTP hydrolysis, and requires the release of GDP before a new cycle can be initiated. For eukaryotic heterotrimeric Gαβγ proteins, the interaction with a membrane-bound G protein-coupled receptor catalyzes the release of GDP from the Gα subunit. Structural and functional studies have implicated one of the nucleotide binding sequence motifs, the G5 motif, as playing an integral part in this release mechanism. Indeed, a Gαs G5 mutant (A366S) was shown to have an accelerated GDP release rate, mimicking a G protein-coupled receptor catalyzed release state. In the present study, we investigate the role of the equivalent residue in the G5 motif (residue A143) in the prokaryotic membrane protein FeoB from Streptococcus thermophilus, which includes an N-terminal soluble G protein domain. The structure of this domain has previously been determined in the apo and GDP-bound states and in the presence of a transition state analogue, revealing conformational changes in the G5 motif. The A143 residue was mutated to a serine and analyzed with respect to changes in GTPase activity, nucleotide release rate, GDP affinity and structural alterations. We conclude that the identity of the residue at this position in the G5 loop plays a key role in the nucleotide release rate by allowing the correct positioning and hydrogen bonding of the nucleotide base.

PubMed: 24649829
DOI: 10.1111/febs.12779

実験手法

X-RAY DIFFRACTION (2.5 Å)