title: Redox-switch regulatory mechanism of thiolase from Clostridium acetobutylicum.
abstract: Thiolase is the first enzyme catalysing the condensation of two acetyl-coenzyme A (CoA) molecules to form acetoacetyl-CoA in a dedicated pathway towards the biosynthesis of n-butanol, an important solvent and biofuel. Here we elucidate the crystal structure of Clostridium acetobutylicum thiolase (CaTHL) in its reduced/oxidized states. CaTHL, unlike those from other aerobic bacteria such as Escherichia coli and Zoogloea ramegera, is regulated by the redox-switch modulation through reversible disulfide bond formation between two catalytic cysteine residues, Cys88 and Cys378. When CaTHL is overexpressed in wild-type C. acetobutylicum, butanol production is reduced due to the disturbance of acidogenic to solventogenic shift. The CaTHL(V77Q/N153Y/A286K) mutant, which is not able to form disulfide bonds, exhibits higher activity than wild-type CaTHL, and enhances butanol production upon overexpression. On the basis of these results, we suggest that CaTHL functions as a key enzyme in the regulation of the main metabolism of C. acetobutylicum through a redox-switch regulatory mechanism.
authors.affiliation: School of Life Sciences, KNU Creative BioResearch Group, Kyungpook National University, Daegu 702-701, Korea.|School of Nano-Bioscience and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 689-798, Korea.
authors.forename: Sangwoo
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Chemical and Biomolecular Engineering (BK21 Plus Program) and BioProcess Engineering Research Center, KAIST, Daejeon 305-701, Korea.
authors.forename: Yu-Sin
authors.initials: YS
authors.lastname: Jang
authors.affiliation: Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang, Kyungbuk 790-784, Korea.
authors.forename: Sung-Chul
authors.initials: SC
authors.lastname: Ha
authors.affiliation: School of Life Sciences, KNU Creative BioResearch Group, Kyungpook National University, Daegu 702-701, Korea.
authors.forename: Jae-Woo
authors.initials: JW
authors.lastname: Ahn
authors.affiliation: School of Life Sciences, KNU Creative BioResearch Group, Kyungpook National University, Daegu 702-701, Korea.
authors.forename: Eun-Jung
authors.initials: EJ
authors.lastname: Kim
authors.affiliation: Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang, Kyungbuk 790-784, Korea.
authors.forename: Jae Hong
authors.initials: JH
authors.lastname: Lim
authors.affiliation: Department of Chemical and Biomolecular Engineering (BK21 Plus Program) and BioProcess Engineering Research Center, KAIST, Daejeon 305-701, Korea.
authors.forename: Changhee
authors.initials: C
authors.lastname: Cho
authors.affiliation: School of Nano-Bioscience and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 689-798, Korea.
authors.forename: Yong Shin
authors.initials: YS
authors.lastname: Ryu
authors.affiliation: School of Nano-Bioscience and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 689-798, Korea.
authors.forename: Sung Kuk
authors.initials: SK
authors.lastname: Lee
authors.affiliation: Department of Chemical and Biomolecular Engineering (BK21 Plus Program) and BioProcess Engineering Research Center, KAIST, Daejeon 305-701, Korea.|Center for Systems and Synthetic Biotechnology, Institute for the BioCentury, and Bioinformatics Research Center, KAIST, Daejeon 305-701, Korea.
authors.forename: Sang Yup
authors.initials: SY
authors.lastname: Lee
authors.affiliation: School of Life Sciences, KNU Creative BioResearch Group, Kyungpook National University, Daegu 702-701, Korea.
authors.forename: Kyung-Jin
authors.initials: KJ
authors.lastname: Kim
mesh_terms: D000217:Acyltransferases / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D046969:Clostridium acetobutylicum / Q000201:enzymology*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D015971:Gene Expression Regulation, Enzymologic; D015394:Molecular Structure; D010084:Oxidation-Reduction; D011487:Protein Conformation
chemical_list: D001426:Bacterial Proteins; D000217:Acyltransferases