3AHG

H64A mutant of Phosphoketolase from Bifidobacterium Breve complexed with a tricyclic ring form of thiamine diphosphate

3AHG の概要

• エントリーDOI: 10.2210/pdb3ahg/pdb
• 関連するPDBエントリー: 3AHC 3AHD 3AHE 3AHF 3AHH 3AHI 3AHJ
• 分子名称: Xylulose 5-phosphate/fructose 6-phosphate phosphoketolase, MAGNESIUM ION, 2-[(9aR)-2,7-dimethyl-9a,10-dihydro-5H-pyrimido[4,5-d][1,3]thiazolo[3,2-a]pyrimidin-8-yl]ethyl trihydrogen diphosphate, ... (6 entities in total)
• 機能のキーワード: thiamine diphosphate-dependent enzyme, alpha-beta fold, homodimer, dihydrothiachromine form of thiamine diphosphate, lyase
• 由来する生物種: Bifidobacterium breve
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 96050.17

構造登録者

Suzuki, R.,Katayama, T.,Kim, B.-J.,Wakagi, T.,Shoun, H.,Ashida, H.,Yamamoto, K.,Fushinobu, S. (登録日: 2010-04-22, 公開日: 2010-08-25, 最終更新日: 2023-11-01)

主引用文献

Suzuki, R.,Katayama, T.,Kim, B.-J.,Wakagi, T.,Shoun, H.,Ashida, H.,Yamamoto, K.,Fushinobu, S.
Crystal Structures of phosphoketolase: thiamine diphosphate-dependent dehydration mechanism
J.Biol.Chem., 285:34279-34287, 2010

PubMed Abstract: Thiamine diphosphate (ThDP)-dependent enzymes are ubiquitously present in all organisms and catalyze essential reactions in various metabolic pathways. ThDP-dependent phosphoketolase plays key roles in the central metabolism of heterofermentative bacteria and in the pentose catabolism of various microbes. In particular, bifidobacteria, representatives of beneficial commensal bacteria, have an effective glycolytic pathway called bifid shunt in which 2.5 mol of ATP are produced per glucose. Phosphoketolase catalyzes two steps in the bifid shunt because of its dual-substrate specificity; they are phosphorolytic cleavage of fructose 6-phosphate or xylulose 5-phosphate to produce aldose phosphate, acetyl phosphate, and H(2)O. The phosphoketolase reaction is different from other well studied ThDP-dependent enzymes because it involves a dehydration step. Although phosphoketolase was discovered more than 50 years ago, its three-dimensional structure remains unclear. In this study we report the crystal structures of xylulose 5-phosphate/fructose 6-phosphate phosphoketolase from Bifidobacterium breve. The structures of the two intermediates before and after dehydration (α,β-dihydroxyethyl ThDP and 2-acetyl-ThDP) and complex with inorganic phosphate give an insight into the mechanism of each step of the enzymatic reaction.

PubMed: 20739284
DOI: 10.1074/jbc.M110.156281

実験手法

X-RAY DIFFRACTION (1.9 Å)