7D50

SpuA mutant - H221N with glutamyl-thioester

7D50 の概要

• エントリーDOI: 10.2210/pdb7d50/pdb
• 分子名称: Probable glutamine amidotransferase, MAGNESIUM ION (3 entities in total)
• 機能のキーワード: spua, gama-glutamyl-gama-aminobutyrate hydrolase, glutamine amidotransferase, pseudomonas aeruginosa pao1., hydrolase
• 由来する生物種: Pseudomonas aeruginosa PAO1
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 54093.95

構造登録者

Chen, Y.,Zhang, Q.,Bartlam, M. (登録日: 2020-09-24, 公開日: 2021-10-06, 最終更新日: 2023-11-29)

主引用文献

Chen, Y.,Jia, H.,Zhang, J.,Liang, Y.,Liu, R.,Zhang, Q.,Bartlam, M.
Structure and mechanism of the gamma-glutamyl-gamma-aminobutyrate hydrolase SpuA from Pseudomonas aeruginosa.
Acta Crystallogr D Struct Biol, 77:1305-1316, 2021

PubMed Abstract: Polyamines are important regulators in all living organisms and are implicated in essential biological processes including cell growth, differentiation and apoptosis. Pseudomonas aeruginosa possesses an spuABCDEFGHI gene cluster that is involved in the metabolism and uptake of two polyamines: spermidine and putrescine. In the proposed γ-glutamylation-putrescine metabolism pathway, SpuA hydrolyzes γ-glutamyl-γ-aminobutyrate (γ-Glu-GABA) to glutamate and γ-aminobutyric acid (GABA). In this study, crystal structures of P. aeruginosa SpuA are reported, confirming it to be a member of the class I glutamine amidotransferase (GAT) family. Activity and substrate-binding assays confirm that SpuA exhibits a preference for γ-Glu-GABA as a substrate. Structures of an inactive H221N mutant were determined with bound glutamate thioester intermediate or glutamate product, thus delineating the active site and substrate-binding pocket and elucidating the catalytic mechanism. The crystal structure of another bacterial member of the class I GAT family from Mycolicibacterium smegmatis (MsGATase) in complex with glutamine was determined for comparison and reveals a binding site for glutamine. Activity assays confirm that MsGATase has activity for glutamine as a substrate but not for γ-Glu-GABA. The work reported here provides a starting point for further investigation of polyamine metabolism in P. aeruginosa.

PubMed: 34605433
DOI: 10.1107/S2059798321008986

実験手法

X-RAY DIFFRACTION (1.77 Å)