title: Ti plasmid and chromosomal ornithine catabolism genes of Agrobacterium tumefaciens C58.
abstract: The pTiC58 plasmid noc genes of Agrobacterium tumefaciens C58 code for nopaline oxidase (nocC), nopaline permease (nocP), the inducible periplasmic protein n1 (nocB), and a function(s) required for ornithine catabolism (nocA). In addition, strains C58 and Ach-5 of A. tumefaciens have chromosomal ornithine catabolism genes. The chromosomal orc gene codes for ornithine dehydrogenase. Strain C58 is normally orc, but orc+ mutants can be selected. We have characterized both chromosomal orc and pTiC58 nocA plasmid genes. Complementation of most chromosomal orc mutants by pTiC58 restored growth on both nopaline and L-ornithine but did not restore ornithine dehydrogenase activity. We conclude that ornithine is an intermediate of nopaline degradation and that the Ti plasmid and chromosome both code for ornithine-degradative enzymes. A model for nopaline catabolism is presented.
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D002876:Chromosomes, Bacterial / Q000502:physiology*; D005796:Genes; D005798:Genes, Bacterial; D007700:Kinetics; D026901:Membrane Transport Proteins / Q000235:genetics*; D009154:Mutation; D009952:Ornithine / Q000378:metabolism*; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000235:genetics*; D010641:Phenotype; D010957:Plasmids; D012231:Rhizobium / Q000235:genetics* / Q000378:metabolism; D013045:Species Specificity
chemical_list: D001426:Bacterial Proteins; D026901:Membrane Transport Proteins; C093725:NocP protein, Agrobacterium tumefaciens; D009952:Ornithine; D000587:Oxidoreductases Acting on CH-NH Group Donors; C021882:nopaline dehydrogenase