1K7X

CRYSTAL STRUCTURE OF THE BETA-SER178PRO MUTANT OF TRYPTOPHAN SYNTHASE

1K7X の概要

• エントリーDOI: 10.2210/pdb1k7x/pdb
• 関連するPDBエントリー: 1K8Y 1K8Z
• 分子名称: TRYPTOPHAN SYNTHASE ALPHA CHAIN, TRYPTOPHAN SYNTHASE BETA CHAIN, SODIUM ION, ... (5 entities in total)
• 機能のキーワード: carbon-oxygen lyase, tryptophan biosynthesis, pyridoxal phosphate, lyase
• 由来する生物種: Salmonella typhimurium; 詳細
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 71766.65

構造登録者

Weyand, M.,Schlichting, I.,Marabotti, A.,Mozzarelli, A. (登録日: 2001-10-22, 公開日: 2002-06-19, 最終更新日: 2023-08-16)

主引用文献

Weyand, M.,Schlichting, I.,Herde, P.,Marabotti, A.,Mozzarelli, A.
Crystal structure of the beta Ser178--> Pro mutant of tryptophan synthase. A "knock-out" allosteric enzyme.
J.Biol.Chem., 277:10653-10660, 2002

PubMed Abstract: The catalytic activity of the pyridoxal 5'-phosphate-dependent tryptophan synthase alpha(2)beta(2) complex is allosterically regulated. The hydrogen bond between the helix betaH6 residue betaSer(178) and the loop alphaL6 residue Gly(181) was shown to be critical in ligand-induced intersubunit signaling, with the alpha-beta communication being completely lost in the mutant betaSer(178) --> Pro (Marabotti, A., De Biase, D., Tramonti, A., Bettati, S., and Mozzarelli, A. (2001) J. Biol. Chem. 276, 17747-17753). The structural basis of the impaired allosteric regulation was investigated by determining the crystal structures of the mutant betaSer(178) --> Pro in the absence and presence of the alpha-subunit ligands indole-3-acetylglycine and glycerol 3-phosphate. The mutation causes local and distant conformational changes especially in the beta-subunit. The ligand-free structure exhibits larger differences at the N-terminal part of helix betaH6, whereas the enzyme ligand complexes show differences at the C-terminal side. In contrast to the wild-type enzyme loop alphaL6 remains in an open conformation even in the presence of alpha-ligands. This effects the equilibrium between active and inactive conformations of the alpha-active site, altering k(cat) and K(m), and forms the structural basis for the missing allosteric communication between the alpha- and beta-subunits.

PubMed: 11756454
DOI: 10.1074/jbc.M111031200

実験手法

X-RAY DIFFRACTION (1.7 Å)