4XEH

Apo structure of KARI from Ignisphaera aggregans

4XEH の概要

• エントリーDOI: 10.2210/pdb4xeh/pdb
• 分子名称: Ketol-acid reductoisomerase (2 entities in total)
• 機能のキーワード: rossmann fold, kari, oxidoreductase
• 由来する生物種: Ignisphaera aggregans
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 38465.51

構造登録者

Cahn, J.K.B.,Brinkmann-Chen, S.,Arnold, F.H. (登録日: 2014-12-23, 公開日: 2015-04-22, 最終更新日: 2023-09-27)

主引用文献

Cahn, J.K.,Brinkmann-Chen, S.,Spatzal, T.,Wiig, J.A.,Buller, A.R.,Einsle, O.,Hu, Y.,Ribbe, M.W.,Arnold, F.H.
Cofactor specificity motifs and the induced fit mechanism in class I ketol-acid reductoisomerases.
Biochem.J., 468:475-484, 2015

PubMed Abstract: Although most sequenced members of the industrially important ketol-acid reductoisomerase (KARI) family are class I enzymes, structural studies to date have focused primarily on the class II KARIs, which arose through domain duplication. In the present study, we present five new crystal structures of class I KARIs. These include the first structure of a KARI with a six-residue β2αB (cofactor specificity determining) loop and an NADPH phosphate-binding geometry distinct from that of the seven- and 12-residue loops. We also present the first structures of naturally occurring KARIs that utilize NADH as cofactor. These results show insertions in the specificity loops that confounded previous attempts to classify them according to loop length. Lastly, we explore the conformational changes that occur in class I KARIs upon binding of cofactor and metal ions. The class I KARI structures indicate that the active sites close upon binding NAD(P)H, similar to what is observed in the class II KARIs of rice and spinach and different from the opening of the active site observed in the class II KARI of Escherichia coli. This conformational change involves a decrease in the bending of the helix that runs between the domains and a rearrangement of the nicotinamide-binding site.

PubMed: 25849365
DOI: 10.1042/BJ20150183

実験手法

X-RAY DIFFRACTION (1.391 Å)