title: Elucidation of the methyl transfer mechanism catalyzed by chalcone O-methyltransferase: a density functional study.
abstract: The mechanism of the methyl transfer catalyzed by chalcone O-methyltransferase has been computationally investigated by employing the hybrid functional B3LYP. Two models are constructed based on the two conformations of the substrate isoliquiritigenin in the X-ray structure. Our calculations show that the overall reaction is divided into two elementary steps: the water-assisted deprotonation of the substrate by His278 as a catalytic base, followed by the methyl transfer from S-adenosyl-L-methionine (SAM) to the substrate. The calculated rate-limiting barriers for the methyl-transfer step indicate that the catalytic reactions are energetically feasible for both conformations adopted by the substrate.
authors.affiliation: State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, China.
authors.forename: Feng-Chao
authors.initials: FC
authors.lastname: Cui
authors.forename: Xiao-Liang
authors.initials: XL
authors.lastname: Pan
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Jing-Yao
authors.initials: JY
authors.lastname: Liu
mesh_terms: D055162:Biocatalysis; D002394:Catechol O-Methyltransferase / Q000737:chemistry / Q000378:metabolism*; D047188:Chalcones / Q000737:chemistry / Q000378:metabolism*; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D015394:Molecular Structure; D011789:Quantum Theory; D012436:S-Adenosylmethionine / Q000737:chemistry / Q000378:metabolism*
chemical_list: D047188:Chalcones; D012436:S-Adenosylmethionine; C040920:isoliquiritigenin; D002394:Catechol O-Methyltransferase