title: A positively charged amino acid at position 129 in nitrilase from Rhodococcus rhodochrous ATCC 33278 is an essential residue for the activity with meta-substituted benzonitriles.
abstract: A positively charged amino acid (Arg, Lys, or His) at position 129 in Rhodococcus rhodochrous ATCC 33278 nitrilase is essential for the activity of aromatic nitriles. The wild-type enzyme containing Arg129 was active only for meta- and para-substituted benzonitriles with a methyl or amino group, but the R129K and R129H mutant enzymes were active only for meta-substituted benzonitriles. The lack of activity of the mutants for para-substituted benzonitriles may be attributable to steric hindrance between the para-substituent and the side chain of Lys or His.
authors.affiliation: Department of Bioscience and Biotechnology, Konkuk University, Seoul, Republic of Korea.
authors.forename: Soo-Jin
authors.initials: SJ
authors.lastname: Yeom
authors.forename: Jung-Kul
authors.initials: JK
authors.lastname: Lee
authors.forename: Deok-Kun
authors.initials: DK
authors.lastname: Oh
mesh_terms: D019943:Amino Acid Substitution; D000619:Aminohydrolases / Q000235:genetics / Q000378:metabolism*; D001120:Arginine / Q000235:genetics / Q000378:metabolism*; D007700:Kinetics; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D009570:Nitriles / Q000378:metabolism*; D012240:Rhodococcus / Q000201:enzymology*
chemical_list: D009570:Nitriles; D001120:Arginine; C014356:benzonitrile; D000619:Aminohydrolases; C076876:aliphatic nitrilase