title: Role of homoserine and threonine pathway intermediates as precursors for the biosynthesis of aminoethoxyvinylglycine in Streptomyces sp. NRRL 5331.
abstract: The genes hom, thrB and thrC, encoding homoserine dehydrogenase, homoserine kinase (HK) and threonine synthase, respectively, involved in the last steps of threonine biosynthesis, have been studied in Streptomyces sp. NRRL 5331, the producer of the ethylene synthetase inhibitor aminoethoxyvinylglycine (AVG), in order to determine their role in the biosynthesis of AVG. Different null mutants were obtained by plasmid-mediated disruption of each of the three genes. thrC gene disruption had no effect on AVG production, while the disruption of thrB blocked HK activity and substantially reduced the yield of this metabolite, probably due to the accumulation of homoserine and/or methionine which have a negative effect on AVG biosynthesis. Disruption of hom (thrA) completely blocked AVG biosynthesis, indicating that homoserine lies at the branching point of the aspartic-acid-derived biosynthetic route that leads to AVG. The four carbon atoms of the vinylglycine moiety of AVG derive, therefore, from homoserine.
authors.affiliation: Institute of Biotechnology INBIOTEC, Parque Científico de León, Avda. del Real, no. 1, 24006 León, Spain.
authors.forename: Mónica
authors.initials: M
authors.lastname: Fernández
authors.affiliation: Institute of Biotechnology INBIOTEC, Parque Científico de León, Avda. del Real, no. 1, 24006 León, Spain.
authors.forename: Yolanda
authors.initials: Y
authors.lastname: Cuadrado
authors.affiliation: Area of Microbiology, Faculty of Biology, University of León, 24071 León, Spain.|Institute of Biotechnology INBIOTEC, Parque Científico de León, Avda. del Real, no. 1, 24006 León, Spain.
authors.forename: Jesús F
authors.initials: JF
authors.lastname: Aparicio
authors.affiliation: Area of Microbiology, Faculty of Biology, University of León, 24071 León, Spain.|Institute of Biotechnology INBIOTEC, Parque Científico de León, Avda. del Real, no. 1, 24006 León, Spain.
authors.forename: Juan F
authors.initials: JF
authors.lastname: Martín
mesh_terms: D019757:Carbon-Oxygen Lyases / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D005998:Glycine / Q000031:analogs & derivatives* / Q000096:biosynthesis*; D006714:Homoserine / Q000378:metabolism*; D006715:Homoserine Dehydrogenase / Q000235:genetics / Q000378:metabolism; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics / Q000378:metabolism; D013302:Streptomyces / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D013912:Threonine / Q000378:metabolism*
chemical_list: D013912:Threonine; D006714:Homoserine; D006715:Homoserine Dehydrogenase; D017853:Phosphotransferases (Alcohol Group Acceptor); C021370:homoserine kinase; D019757:Carbon-Oxygen Lyases; C023160:threonine synthase; C088137:aminoethoxyvinylglycine; D005998:Glycine