title: Functional evaluation of Asp76, 84, 102 and 150 in human arsenic(III) methyltransferase (hAS3MT) interacting with S-adenosylmethionine.
abstract: We prepared eight mutants (D76P, D76N, D84P, D84N, D102P, D102N, D150P and D150N) to investigate the functions of residues Asp76, 84, 102 and 150 in human arsenic(III) methyltransferase (hAS3MT) interacting with the S-adenosylmethionine (SAM)-binding. The affinity of all the mutants for SAM were weakened. All the mutants except for D150N completely lost their methylation activities. Residues Asp76, 84, 102 and 150 greatly influenced hAS3MT catalytic activity via affecting SAM-binding or methyl transfer. Asp76 and 84 were located in the SAM-binding pocket, and Asp102 significantly affected SAM-binding via forming hydrogen bonds with SAM.
authors.affiliation: State Key Laboratory of Coordination Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China.
authors.forename: Xiangli
authors.initials: X
authors.lastname: Li
authors.forename: Zhirong
authors.initials: Z
authors.lastname: Geng
authors.forename: Shuping
authors.initials: S
authors.lastname: Wang
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Song
authors.forename: Xin
authors.initials: X
authors.lastname: Hu
authors.forename: Zhilin
authors.initials: Z
authors.lastname: Wang
mesh_terms: D019943:Amino Acid Substitution; D001151:Arsenic / Q000737:chemistry; D020134:Catalytic Domain; D002942:Circular Dichroism; D006801:Humans; D006860:Hydrogen Bonding; D007700:Kinetics; D008745:Methylation; D008780:Methyltransferases / Q000737:chemistry* / Q000235:genetics; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D011485:Protein Binding; D017433:Protein Structure, Secondary; D012436:S-Adenosylmethionine / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D012436:S-Adenosylmethionine; D008780:Methyltransferases; C505756:AS3MT protein, human; D001151:Arsenic