title: Site-directed mutagenesis of the aspartokinase gene lysC and its characterization in Brevibacterium flavum.
abstract: Using overlap extension polymerase chain reaction (PCR), five transformants of Escherichia coli containing site-directed mutagenized lysC beta gene were generated and analysed. Exchange of C to A and C to T at nucleotide 1118 of the mutated lysC beta gene causes a substitution of serine301 in the wild-type enzyme for tyrosine301 and phenylalanine301 in the mutant enzymes, respectively. Enzyme assays showed that Brevibacterium flavum cells harbouring pSUMN18 with mutated lysC beta genes exhibited 16-20 fold lower specific activities of aspartokinase as compared to that of host containing wild-type lysC gene. The mutation introduced into lysC beta of B. flavum CCRC 18271 resulted in partial feedback-resistant aspartokinase activity.
authors.affiliation: Culture Collection and Research Center, Food Industry Research and and Development Institute, Hsinchu, Taiwan.
authors.forename: J H
authors.initials: JH
authors.lastname: Lu
authors.forename: C C
authors.initials: CC
authors.lastname: Liao
mesh_terms: D001222:Aspartate Kinase / Q000235:genetics* / Q000378:metabolism; D001951:Brevibacterium / Q000235:genetics*; D004269:DNA, Bacterial / Q000032:analysis; D004926:Escherichia coli / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D016297:Mutagenesis, Site-Directed; D010649:Phenylalanine / Q000235:genetics; D010957:Plasmids; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D012694:Serine / Q000235:genetics; D014170:Transformation, Genetic; D014443:Tyrosine / Q000235:genetics
chemical_list: D004269:DNA, Bacterial; D014443:Tyrosine; D012694:Serine; D010649:Phenylalanine; D001222:Aspartate Kinase