6JX2 image
Entry Detail
PDB ID:
6JX2
Keywords:
Title:
Crystal structure of Ketol-acid reductoisomerase from Corynebacterium glutamicum
Biological Source:
PDB Version:
Deposition Date:
2019-04-22
Release Date:
2019-08-07
Method Details:
Experimental Method:
Resolution:
2.60 Å
R-Value Free:
0.26
R-Value Work:
0.17
R-Value Observed:
0.18
Space Group:
P 21 21 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Ketol-acid reductoisomerase (NADP(+))
Chain IDs:A, B, C, D
Chain Length:344
Number of Molecules:4
Biological Source:Corynebacterium glutamicum ATCC 13032
Primary Citation
Crystal Structure and Biochemical Characterization of Ketol-Acid Reductoisomerase fromCorynebacterium glutamicum.
J.Agric.Food Chem. 67 8527 8535 (2019)
PMID: 31298526 DOI: 10.1021/acs.jafc.9b03262

Abstact

l-Valine belongs to the branched-chain amino acids (BCAAs) and is an essential amino acid that is crucial for all living organisms. l-Valine is industrially produced by the nonpathogenic bacterium Corynebacterium glutamicum and is synthesized by the BCAA biosynthetic pathway. Ketol-acid reductoisomerase (KARI) is the second enzyme in the BCAA pathway and catalyzes the conversion of (S)-2-acetolactate into (R)-2,3-dihydroxy-isovalerate, or the conversion of (S)-2-aceto-2-hydroxybutyrate into (R)-2,3-dihydroxy-3-methylvalerate. To elucidate the enzymatic properties of KARI from C. glutamicum (CgKARI), we successfully produced CgKARI protein and determined its crystal structure in complex with NADP+ and two Mg2+ ions. Based on the complex structure, docking simulations, and site-directed mutagenesis experiments, we revealed that CgKARI belongs to Class I KARI and identified key residues involved in stabilization of the substrate, metal ions, and cofactor. Furthermore, we confirmed the difference in the binding of metal ions that depended on the conformational change.

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