title: Cloning and characterization of the Escherichia coli K-12 alanine-valine transaminase (avtA) gene.
abstract: avtA, which encodes the alanine-valine transaminase, transaminase C, was cloned in vivo with high- and low-copy-number mini-Mu cloning vectors. The phenotype conferred by the cloned avtA+ gene usually depended upon the plasmid copy number; most high-copy-number avtA+ plasmids permitted isoleucine-requiring ilvE strains to grow in the absence of isoleucine (multicopy suppression), while low-copy-number avtA+ plasmids did not. avtA was mapped to a 1.25-kilobase segment by comparison of the restriction maps of 24 independent mini-Mu plasmids and then by gamma-delta (Tn1000) mutagenesis of a pBR322-avtA+ plasmid. The direction of transcription of avtA on the cloned fragment was determined with fusions to a promoterless lac gene.
mesh_terms: D002874:Chromosome Mapping; D003001:Cloning, Molecular; D004262:DNA Restriction Enzymes; D004251:DNA Transposable Elements; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D005786:Gene Expression Regulation; D005798:Genes, Bacterial; D009154:Mutation; D010641:Phenotype; D010957:Plasmids; D000637:Transaminases / Q000096:biosynthesis / Q000235:genetics*; D014158:Transcription, Genetic; D014161:Transduction, Genetic
chemical_list: D004251:DNA Transposable Elements; D000637:Transaminases; C034522:valine-pyruvate transaminase; D004262:DNA Restriction Enzymes