title: Crystal structure of archaeal ketopantoate reductase complexed with coenzyme a and 2-oxopantoate provides structural insights into feedback regulation.
abstract: Coenzyme A (CoA) plays essential roles in a variety of metabolic pathways in all three domains of life. The biosynthesis pathway of CoA is strictly regulated by feedback inhibition. In bacteria and eukaryotes, pantothenate kinase is the target of feedback inhibition by CoA. Recent biochemical studies have identified ketopantoate reductase (KPR), which catalyzes the NAD(P)H-dependent reduction of 2-oxopantoate to pantoate, as a target of the feedback inhibition by CoA in archaea. However, the mechanism for recognition of CoA by KPR is still unknown. Here we report the crystal structure of KPR from Thermococcus kodakarensis in complex with CoA and 2-oxopantoate. CoA occupies the binding site of NAD(P)H, explaining the competitive inhibition by CoA. Our structure reveals a disulfide bond between CoA and Cys84 that indicates an irreversible inhibition upon binding of CoA. The structure also suggests the cooperative binding of CoA and 2-oxopantoate that triggers a conformational closure and seems to facilitate the disulfide bond formation. Our findings provide novel insights into the mechanism that regulates biosynthesis of CoA in archaea.
authors.affiliation: Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-Ku, Kyoto, 606-8502, Japan.
authors.forename: Yoshiki
authors.initials: Y
authors.lastname: Aikawa
authors.affiliation: Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-Ku, Kyoto, 606-8502, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Nishitani
authors.affiliation: Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-Ku, Kyoto, 615-8510, Japan.
authors.forename: Hiroya
authors.initials: H
authors.lastname: Tomita
authors.affiliation: Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-Ku, Kyoto, 615-8510, Japan.|JST, CREST, 7, Gobancho, Chiyoda-Ku, Tokyo, 102-0076, Japan.
authors.forename: Haruyuki
authors.initials: H
authors.lastname: Atomi
authors.affiliation: Department of Chemistry, Graduate School of Science, Kyoto University, Sakyo-Ku, Kyoto, 606-8502, Japan.|JST, CREST, 7, Gobancho, Chiyoda-Ku, Tokyo, 102-0076, Japan.
authors.forename: Kunio
authors.initials: K
authors.lastname: Miki
mesh_terms: D000429:Alcohol Oxidoreductases / Q000737:chemistry*; D000595:Amino Acid Sequence; D019843:Archaeal Proteins / Q000737:chemistry*; D020134:Catalytic Domain; D003065:Coenzyme A / Q000737:chemistry*; D018360:Crystallography, X-Ray; D025461:Feedback, Physiological; D006885:Hydroxybutyrates / Q000737:chemistry*; D007700:Kinetics; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D013379:Substrate Specificity
chemical_list: D019843:Archaeal Proteins; D006885:Hydroxybutyrates; C016031:pantoic acid; D000429:Alcohol Oxidoreductases; C021934:2-dehydropantoate 2-reductase; D003065:Coenzyme A
keywords: competitive inhibition; conformational closure; feedback inhibition; hyperthermophilic archaea; irreversible binding