1IBT

STRUCTURE OF THE D53,54N MUTANT OF HISTIDINE DECARBOXYLASE AT-170 C

1IBT の概要

• エントリーDOI: 10.2210/pdb1ibt/pdb
• 関連するPDBエントリー: 1HQ6 1IBU 1IBV 1IBW 1PYA
• 分子名称: HISTIDINE DECARBOXYLASE BETA CHAIN, HISTIDINE DECARBOXYLASE ALPHA CHAIN (3 entities in total)
• 機能のキーワード: helix disorder, less active form, site-directed mutant, pyruvoyl, carboxy-lyase, lyase
• 由来する生物種: Lactobacillus sp.; 詳細
• タンパク質・核酸の鎖数: 6
• 化学式量合計: 102402.71

構造登録者

Worley, S.,Schelp, E.,Monzingo, A.F.,Ernst, S.,Robertus, J.D. (登録日: 2001-03-29, 公開日: 2002-03-13, 最終更新日: 2024-10-30)

主引用文献

Worley, S.,Schelp, E.,Monzingo, A.F.,Ernst, S.,Robertus, J.D.
Structure and cooperativity of a T-state mutant of histidine decarboxylase from Lactobacillus 30a.
Proteins, 46:321-329, 2002

PubMed Abstract: Histidine decarboxylase (HDC) from Lactobacillus 30a converts histidine to histamine, a process that enables the bacteria to maintain the optimum pH range for cell growth. HDC is regulated by pH; it is active at low pH and inactive at neutral to alkaline pH. The X-ray structure of HDC at pH 8 revealed that a helix was disordered, resulting in the disruption of the substrate-binding site. The HDC trimer has also been shown to exhibit cooperative kinetics at neutral pH, that is, histidine can trigger a T-state to R-state transition. The D53,54N mutant of HDC has an elevated Km, even at low pH, indicating that the enzyme assumes the low activity T-state. We have solved the structures of the D53,54N mutant at low pH, with and without the substrate analog histidine methyl ester (HME) bound. Structural analysis shows that the apo-D53,54N mutant is in the inactive or T-state and that binding of the substrate analog induces the enzyme to adopt the active or R-state. A mechanism for the cooperative transition is proposed.

PubMed: 11835507
DOI: 10.1002/prot.10042

実験手法

X-RAY DIFFRACTION (2.6 Å)