3KXI

crystal structure of SsGBP and GDP complex

3KXI の概要

• エントリーDOI: 10.2210/pdb3kxi/pdb
• 関連するPDBエントリー: 2QTH 3KXK 3KXL
• 分子名称: GTP-binding protein (HflX), MAGNESIUM ION, GUANOSINE-5'-DIPHOSPHATE, ... (5 entities in total)
• 機能のキーワード: ssgbp, hflx, gtpase, mg++ ion binding site, gtp-binding, nucleotide binding protein
• 由来する生物種: Sulfolobus solfataricus
• 細胞内の位置: Cytoplasm : Q980M3
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 42190.18

構造登録者

Huang, B.,Li, X.,Zhang, X.C.,Rao, Z. (登録日: 2009-12-03, 公開日: 2010-05-26, 最終更新日: 2024-03-20)

主引用文献

Huang, B.,Wu, H.,Hao, N.,Blombach, F.,van der Oost, J.,Li, X.,Zhang, X.C.,Rao, Z.
Functional study on GTP hydrolysis by the GTP binding protein from Sulfolobus solfataricus, a member of the HflX family.
J.Biochem., 2010

PubMed Abstract: GTPase domains from members of the HflX protein family have their catalytic glutamine residue of the DxxGQ motif substituted by phenylalanine, while they are still able to hydrolyse GTP. This appears to challenge the traditional view of GTP hydrolysis mechanism of Ras-like GTPases. SsGBP from the hyperthermophilic archaeon Sulfolobus solfataricus provided the first crystal structure of the HflX family. Here, we report structure-based mutagenesis analyses on SsGBP. Six-point mutations were individually introduced in the Ras-like GTPase domain including regions of P-loop, switches I and II. Intrinsic GTPase activities and thermal stabilities of these variants together with the wild-type full-length SsGBP and its isolated GTPase domain were analysed. Both functional and structural analyses of G235P and G235S mutants, which showed total and partial loss of the GTP hydrolyzing activity, respectively, support our hypothesis that the role of aligning a nucleophilic water molecule by the Ras Gln60 residue is replaced by the backbone amide group of Gly235 in SsGBP. Together with functional studies of other mutants, we conclude that the classical view of GTP hydrolysis mechanism likely remains the same in the HflX family with a twist in the entity of the nucleophilic alignment.

PubMed: 20400571
DOI: 10.1093/jb/mvq039

実験手法

X-RAY DIFFRACTION (2.65 Å)