Structural and functional analysis of a FeoB A143S G5 loop mutant explains the accelerated GDP release rate

Guilfoyle, Amy P., Deshpande, Chandrika N., Vincent, Kimberley, Pedroso, Marcelo M., Schenk, Gerhard, Maher, Megan J. and Jormakka, Mika (2014) Structural and functional analysis of a FeoB A143S G5 loop mutant explains the accelerated GDP release rate. FEBS Journal, 281 9: 2254-2265. doi:10.1111/febs.12779

Author Guilfoyle, Amy P.
Deshpande, Chandrika N.
Vincent, Kimberley
Pedroso, Marcelo M.
Schenk, Gerhard
Maher, Megan J.
Jormakka, Mika
Title Structural and functional analysis of a FeoB A143S G5 loop mutant explains the accelerated GDP release rate
Journal name FEBS Journal   Check publisher's open access policy
ISSN 1742-464X
Publication date 2014-05
Sub-type Article (original research)
DOI 10.1111/febs.12779
Open Access Status
Volume 281
Issue 9
Start page 2254
End page 2265
Total pages 12
Place of publication Chichester, West Sussex, United Kingdom
Publisher Wiley-Blackwell Publishing
Collection year 2015
Language eng
Formatted 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.
Keyword Crystal structure
GDP release
Isothermal titration calorimetry
Protein motifs
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: Official 2015 Collection
School of Chemistry and Molecular Biosciences
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Citation counts: TR Web of Science Citation Count  Cited 3 times in Thomson Reuters Web of Science Article | Citations
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Created: Wed, 09 Apr 2014, 10:58:09 EST by Mrs Louise Nimwegen on behalf of School of Chemistry & Molecular Biosciences