6jx2

From Proteopedia

Crystal structure of Ketol-acid reductoisomerase from Corynebacterium glutamicum

Structural highlights

6jx2 is a 4 chain structure with sequence from Corynebacterium glutamicum ATCC 13032. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 2.6Å
Ligands:	, ,
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

ILVC_CORGL Involved in the biosynthesis of branched-chain amino acids (BCAA). Catalyzes an alkyl-migration followed by a ketol-acid reduction of (S)-2-acetolactate (S2AL) to yield (R)-2,3-dihydroxy-isovalerate. In the isomerase reaction, S2AL is rearranged via a Mg-dependent methyl migration to produce 3-hydroxy-3-methyl-2-ketobutyrate (HMKB). In the reductase reaction, this 2-ketoacid undergoes a metal-dependent reduction by NADPH to yield (R)-2,3-dihydroxy-isovalerate.[HAMAP-Rule:MF_00435]

Publication Abstract from PubMed

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 Mg(2+) 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.

Crystal Structure and Biochemical Characterization of Ketol-Acid Reductoisomerase from Corynebacterium glutamicum.,Lee D, Hong J, Kim KJ J Agric Food Chem. 2019 Jul 25. doi: 10.1021/acs.jafc.9b03262. PMID:31298526^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Lee D, Hong J, Kim KJ. Crystal Structure and Biochemical Characterization of Ketol-Acid Reductoisomerase from Corynebacterium glutamicum. J Agric Food Chem. 2019 Jul 25. doi: 10.1021/acs.jafc.9b03262. PMID:31298526 doi:http://dx.doi.org/10.1021/acs.jafc.9b03262