4LNI

B. subtilis glutamine synthetase structures reveal large active site conformational changes and basis for isoenzyme specific regulation: structure of the transition state complex

4LNI の概要

• エントリーDOI: 10.2210/pdb4lni/pdb
• 関連するPDBエントリー: 4LNF 4LNK 4LNN 4LNO
• 分子名称: Glutamine synthetase, L-METHIONINE-S-SULFOXIMINE PHOSPHATE, ADENOSINE-5'-DIPHOSPHATE, ... (5 entities in total)
• 機能のキーワード: alpha-beta, tnra, glnra, ligase
• 由来する生物種: Bacillus subtilis
• タンパク質・核酸の鎖数: 12
• 化学式量合計: 611606.72

構造登録者

Schumacher, M.A.,Chinnam, N.,Tonthat, N.,Fisher, S.,Wray, L. (登録日: 2013-07-11, 公開日: 2013-11-06, 最終更新日: 2024-02-28)

主引用文献

Murray, D.S.,Chinnam, N.,Tonthat, N.K.,Whitfill, T.,Wray, L.V.,Fisher, S.H.,Schumacher, M.A.
Structures of the Bacillus subtilis Glutamine Synthetase Dodecamer Reveal Large Intersubunit Catalytic Conformational Changes Linked to a Unique Feedback Inhibition Mechanism.
J.Biol.Chem., 288:35801-35811, 2013

PubMed Abstract: Glutamine synthetase (GS), which catalyzes the production of glutamine, plays essential roles in nitrogen metabolism. There are two main bacterial GS isoenzymes, GSI-α and GSI-β. GSI-α enzymes, which have not been structurally characterized, are uniquely feedback-inhibited by Gln. To gain insight into GSI-α function, we performed biochemical and cellular studies and obtained structures for all GSI-α catalytic and regulatory states. GSI-α forms a massive 600-kDa dodecameric machine. Unlike other characterized GS, the Bacillus subtilis enzyme undergoes dramatic intersubunit conformational alterations during formation of the transition state. Remarkably, these changes are required for active site construction. Feedback inhibition arises from a hydrogen bond network between Gln, the catalytic glutamate, and the GSI-α-specific residue, Arg(62), from an adjacent subunit. Notably, Arg(62) must be ejected for proper active site reorganization. Consistent with these findings, an R62A mutation abrogates Gln feedback inhibition but does not affect catalysis. Thus, these data reveal a heretofore unseen restructuring of an enzyme active site that is coupled with an isoenzyme-specific regulatory mechanism. This GSI-α-specific regulatory network could be exploited for inhibitor design against Gram-positive pathogens.

PubMed: 24158439
DOI: 10.1074/jbc.M113.519496

実験手法

X-RAY DIFFRACTION (2.5793 Å)