title: The clavulanic acid biosynthetic cluster of Streptomyces clavuligerus: genetic organization of the region upstream of the car gene.
abstract: The genetic organization of the region upstream of the car gene of the clavulanic acid biosynthetic gene cluster of Streptomyces clavuligerus has been determined. Sequence analysis of a 12.1 kb region revealed the presence of 10 ORFs whose putative functions, according to database searches, are discussed. Three co-transcriptional units are proposed: ORF10-11, ORF12-13 and ORF15-16-17-18. Potential transcriptional terminators were identified downstream of ORF11 (fd) and ORF15. Targeted disruption of ORF10 (cyp) gave rise to transformants unable to produce clavulanic acid, but with a considerably higher production of cephamycin C. Transformants inactivated at ORF14 had a remarkably lower production of clavulanic acid and similar production of cephamycin C. Significant improvements of clavulanic acid production, associated with a drop in cephamycin C biosynthesis, were obtained with transformants of S. clavuligerus harbouring multiple copies of plasmids carrying different constructions from the ORF10-14 region. This information can be used to guide strain improvement programs, blending random mutagenesis and molecular cloning, to optimize the yield of clavulanic acid.
authors: Área de Biotecnologı́a, Antibióticos SA, Avenida de Antibióticos 59-61, 24009 León, Spain1.
authors: Encarnación
authors: E
authors: Mellado
authors: Área de Microbiologı́a, Facultad de Biologı́a, Universidad de León, 24071 León, Spain2.
authors: Luis Miguel
authors: LM
authors: Lorenzana
authors: Área de Biotecnologı́a, Antibióticos SA, Avenida de Antibióticos 59-61, 24009 León, Spain1.
authors: Marta
authors: M
authors: Rodrı Guez-Sáiz
authors: Área de Biotecnologı́a, Antibióticos SA, Avenida de Antibióticos 59-61, 24009 León, Spain1.
authors: Bruno
authors: B
authors: Dı Ez
authors: Área de Microbiologı́a, Facultad de Biologı́a, Universidad de León, 24071 León, Spain2.
authors: Paloma
authors: P
authors: Liras
authors: Área de Biotecnologı́a, Antibióticos SA, Avenida de Antibióticos 59-61, 24009 León, Spain1.
authors: José Luis
authors: JL
authors: Barredo
mesh_terms: D001483:Base Sequence; D002513:Cephamycins / Q000096:biosynthesis; D019818:Clavulanic Acid / Q000096:biosynthesis*; D015870:Gene Expression; D015964:Gene Expression Regulation, Bacterial; D023061:Gene Order; D005798:Genes, Bacterial / Q000235:genetics*; D015698:Genomic Library; D008969:Molecular Sequence Data; D016366:Open Reading Frames / Q000235:genetics*; D010957:Plasmids / Q000235:genetics; D017422:Sequence Analysis, DNA; D013302:Streptomyces / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism*; D014158:Transcription, Genetic / Q000235:genetics; D014169:Transformation, Bacterial
chemical_list: D002513:Cephamycins; D019818:Clavulanic Acid