title: Biotin biosynthesis, transport and utilization in rhizobia.
abstract: Biotin, a B-group vitamin, performs an essential metabolic function in all organisms. Rhizobia are alpha-proteobacteria with the remarkable ability to form a nitrogen-fixing symbiosis in combination with a compatible legume host, a process in which the importance of biotin biosynthesis and/or transport has been demonstrated for some rhizobia-legume combinations. Rhizobia have also been used to delimit the biosynthesis, metabolic effects and, more recently, transport of biotin. Molecular genetic analysis shows that an orthodox biotin biosynthesis pathway occurs in some rhizobia while others appear to synthesize the vitamin using alternative pathways. In addition to its well established function as a prosthetic group for biotin-dependent carboxylases, we are beginning to delineate a role for biotin as a metabolic regulator in rhizobia.
authors.affiliation: Programa de Ingeniería Metabólica, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, A.P. 565-A, Cuernavaca, Morelos, Mexico.
authors.forename: Karina
authors.initials: K
authors.lastname: Guillén-Navarro
authors.forename: Sergio
authors.initials: S
authors.lastname: Encarnación
authors.forename: Michael F
authors.initials: MF
authors.lastname: Dunn
mesh_terms: D001692:Biological Transport; D001710:Biotin / Q000096:biosynthesis / Q000378:metabolism; D007887:Fabaceae / Q000382:microbiology; D012231:Rhizobium / Q000235:genetics / Q000378:metabolism*; D013559:Symbiosis
chemical_list: D001710:Biotin