title: Characterization and cofactor binding mechanism of a novel NAD(P)H-dependent aldehyde reductase from Klebsiella pneumoniae DSM2026.
abstract: During the fermentative production of 1,3-propanediol under high substrate concentrations, accumulation of intracellular 3-hydroxypropionaldehyde will cause premature cessation of cell growth and glycerol consumption. Discovery of oxidoreductases that can convert 3- hydroxypropionaldehyde to 1,3-propanediol using NADPH as cofactor could serve as a solution to this problem. In this paper, the yqhD gene from Klebsiella pneumoniae DSM2026, which was found encoding an aldehyde reductase (KpAR), was cloned and characterized. KpAR showed broad substrate specificity under physiological direction, whereas no catalytic activity was detected in the oxidation direction, and both NADPH and NADH can be utilized as cofactors. The cofactor binding mechanism was then investigated employing homology modeling and molecular dynamics simulations. Hydrogen-bond analysis showed that the hydrogen-bond interactions between KpAR and NADPH are much stronger than that for NADH. Free-energy decomposition dedicated that residues Gly37 to Val41 contribute most to the cofactor preference through polar interactions. In conclusion, this work provides a novel aldehyde reductase that has potential applications in the development of novel genetically engineered strains in the 1,3-propanediol industry, and gives a better understanding of the mechanisms involved in cofactor binding.
authors.affiliation: School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116024, China.
authors.forename: Cheng-Wei
authors.initials: CW
authors.lastname: Ma
authors.forename: Le
authors.initials: L
authors.lastname: Zhang
authors.forename: Jian-Ying
authors.initials: JY
authors.lastname: Dai
authors.forename: Zhi-Long
authors.initials: ZL
authors.lastname: Xiu
mesh_terms: D000429:Alcohol Oxidoreductases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D003067:Coenzymes / Q000737:chemistry / Q000378:metabolism*; D005985:Glyceraldehyde / Q000031:analogs & derivatives / Q000378:metabolism; D007711:Klebsiella pneumoniae / Q000201:enzymology* / Q000235:genetics; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D009243:NAD / Q000737:chemistry / Q000378:metabolism*; D009249:NADP / Q000737:chemistry / Q000378:metabolism*; D011407:Propane / Q000378:metabolism; D011409:Propylene Glycols / Q000378:metabolism*; D011485:Protein Binding; D055672:Static Electricity; D013379:Substrate Specificity
chemical_list: D003067:Coenzymes; D011409:Propylene Glycols; D009243:NAD; C047158:3-hydroxypropionaldehyde; D005985:Glyceraldehyde; D009249:NADP; C041787:1,3-propanediol; D000429:Alcohol Oxidoreductases; C019642:alcohol dehydrogenase (NADP+); D011407:Propane