Genes encoding two ribonucleotide reductases (RNRs) were identified in members of the genus Streptomyces. One gene, nrdJ, encoded an oligomeric protein comprising four identical subunits each with a molecular mass of approximately 108 kDa. The activity of this protein depended on the presence of 5'-deoxyadenosylcobalamine (coenzyme B12), establishing it as a class II RNR. The Streptomyces clavu...

clavulanic acid is produced industrially by fermentation of streptomyces clavuligerus and researches have increased its production by strain improvement, recombinant dna technology, and media composition and growth condition optimization. the main objective of this study was to increase the level of clavulanic acid production from streptomyces clavuligerus (dsm 738), using uv irradiation. after...

Negative control of clavulanic acid by phosphate in Streptomyces clavuligerus DSM 738 suggests that a pho regulon may exist in this bacterium. S. clavuligerus PhoP was expressed with a C-terminal His-tag in Escherichia coli and purified. Binding of PhoP-His 6 to promoter fragments of phoRP/phoU and pstS was demonstrated in gel retardation experiments. These fragments contained direct 11 bp repe...

orf7 (oppA1) and orf15 (oppA2) are located 8 kb apart in the clavulanic acid gene cluster of Streptomyces clavuligerus and encode proteins which are 48.0% identical. These proteins show sequence similarity to periplasmic oligopeptide-binding proteins. Mutant S. clavuligerus oppA1::acc, disrupted in oppA1, lacks clavulanic acid production. Clavulanic acid production is restored by transformation...

The tlrB gene from Streptomyces fradiae has been cloned and used to construct bifunctional Streptomyces-Escherichia coli shuttle vectors carrying the antibiotic resistance genes to kanamycin-neomycin, thiostrepton and tylosin as selection markers. In the same way, the tlrB gene was subcloned in plasmids including the apramycin resistance gene and the oriT sequence from the plasmid pSET152 to fa...

To develop a strategy for improved production of clavulanic acid (CA), we investigated the effect of using oils on cell growth and CA production during the fermentation of Streptomyces clavuligerus NRRL 3585. In this analysis, triolein, whose fatty acid is oleic acid only, was the best oil source for CA production, but free fatty acids generated from the hydrolysis of oils in a culture broth ne...

Portions of the Streptomyces clavuligerus chromosome flanking cas1, which encodes the clavaminate synthase 1 isoenzyme (CAS1), have been cloned and sequenced. Mutants of S. clavuligerus disrupted in cvm1, the open reading frame located immediately upstream of cas1, were constructed by a gene replacement procedure. Similar techniques were used to generate S. clavuligerus mutants carrying a delet...