title: Cloning of genes that suppress an Escherichia coli K-12 alanine auxotroph when present in multicopy plasmids.
abstract: To facilitate molecular analyses of a previously uncharacterized gene involved in alanine synthesis, attempts were made to clone the wild-type allele of this gene, alaA, with a mini-Mu plasmid element used for in vivo cloning. Seventy-six independent Ala+ plasmids were isolated and characterized. Physiological, enzymological, and restriction endonuclease analyses indicated that three different genes, none of them alaA, were cloned. These genes were avtA+, which encodes the alanine-valine transaminase (transaminase C); tyrB+, which encodes the tyrosine-repressible transaminase (transaminase D); and a previously undescribed gene, called alaB, which encodes an alanine-glutamate transaminase.
mesh_terms: D000409:Alanine / Q000096:biosynthesis* / Q000235:genetics; D000410:Alanine Transaminase / Q000235:genetics; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D005798:Genes, Bacterial; D007532:Isoleucine / Q000235:genetics; D010957:Plasmids; D000637:Transaminases / Q000235:genetics*; D014161:Transduction, Genetic; D014444:Tyrosine Transaminase / Q000235:genetics
chemical_list: D007532:Isoleucine; D000637:Transaminases; D000410:Alanine Transaminase; D014444:Tyrosine Transaminase; C034522:valine-pyruvate transaminase; D000409:Alanine