5GK0

Crystal structure of selnomethionin-labeled ketosynthase StlD

5GK0 の概要

• エントリーDOI: 10.2210/pdb5gk0/pdb
• 関連するPDBエントリー: 5GK1 5GK2
• 分子名称: Ketosynthase StlD (2 entities in total)
• 機能のキーワード: ketosynthase, transferase
• 由来する生物種: Photorhabdus luminescens subsp. laumondii
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 181947.44

構造登録者

Mori, T.,Saito, Y.,Morita, H.,Abe, I. (登録日: 2016-07-03, 公開日: 2017-07-05, 最終更新日: 2024-10-09)

主引用文献

Mori, T.,Awakawa, T.,Shimomura, K.,Saito, Y.,Yang, D.,Morita, H.,Abe, I.
Structural Insight into the Enzymatic Formation of Bacterial Stilbene.
Cell Chem Biol, 23:1468-1479, 2016

PubMed Abstract: In contrast to stilbene biosynthesis by type III polyketide synthase in plants, in bacteria stilbene is produced by the collaboration of two enzymes in Photorhabdus luminescens: the unusual β-ketosynthase StlD catalyzes the condensation of the β-ketoacyl starter with an α,β-unsaturated-acyl substrate (two C-C bond-forming reactions) to produce isopropylstyrylcyclohexanedione, which is subsequently converted to stilbene by the aromatase StlC. Here we report the in vitro characterizations of StlD and StlC, and the X-ray crystal structures of StlD. Interestingly, structure-based mutagenesis demonstrated that His302, within the conserved Cys-His-Asn triad, is not essential for the enzyme reaction, while Glu154 functions as a base-catalyst to activate the β-ketoacyl intermediate bound to the catalytic Cys126. The structures also revealed the presence of a putative nucleophilic water molecule activated by hydrogen bond networks with Glu154 and Ser340, suggesting that StlD employs novel catalytic machinery for the condensation of two acyl substrates to produce the cyclohexanedione scaffold.

PubMed: 27866911
DOI: 10.1016/j.chembiol.2016.10.010

実験手法

X-RAY DIFFRACTION (2.331 Å)