1KKB

Complex of Escherichia coli Adenylosuccinate Synthetase with IMP and Hadacidin

1KKB の概要

• エントリーDOI: 10.2210/pdb1kkb/pdb
• 関連するPDBエントリー: 1CIB 1KJX
• 分子名称: Adenylosuccinate Synthetase, HADACIDIN, INOSINIC ACID, ... (4 entities in total)
• 機能のキーワード: ligase, gtp-hydrolysing enzymes, purine nucleotide, biosynthesis, induced fit
• 由来する生物種: Escherichia coli K12
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 47868.07

構造登録者

Hou, Z.,Wang, W.,Fromm, H.J.,Honzatko, R.B. (登録日: 2001-12-06, 公開日: 2002-03-20, 最終更新日: 2024-02-14)

主引用文献

Hou, Z.,Wang, W.,Fromm, H.J.,Honzatko, R.B.
IMP Alone Organizes the Active Site of Adenylosuccinate Synthetase from Escherichia coli.
J.Biol.Chem., 277:5970-5976, 2002

PubMed Abstract: A complete set of substrate/substrate analogs of adenylosuccinate synthetase from Escherichia coli induces dimer formation and a transition from a disordered to an ordered active site. The most striking of the ligand-induced effects is the movement of loop 40-53 by up to 9 A. Crystal structures of the partially ligated synthetase, which either combine IMP and hadacidin or IMP, hadacidin, and Mg(2+)-pyrophosphate, have ordered active sites, comparable with the fully ligated enzyme. More significantly, a crystal structure of the synthetase with IMP alone exhibits a largely ordered active site, which includes the 9 A movement of loop 40-53 but does not include conformational adjustments to backbone carbonyl 40 (Mg(2+) interaction element) and loop 298-304 (L-aspartate binding element). Interactions involving the 5'-phosphoryl group of IMP evidently trigger the formation of salt links some 30 A away. The above provides a structural basis for ligand binding synergism, effects on k(cat) due to mutations far from the site of catalysis, and the complete loss of substrate efficacy due to minor alterations of the 5'-phosphoryl group of IMP.

PubMed: 11741996
DOI: 10.1074/jbc.M109561200

実験手法

X-RAY DIFFRACTION (2.6 Å)