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ABSTRACT: A 6.0 kb DNA fragment related to nikkomycin biosynthesis was cloned from nikkomycin-producingStreptomyces ansochromogenes 7100. Sequence analysis showed that the 1.9 kbTth111 I fragment, a part of the 6.0 kb DNA fragment, contains one complete ORF designatedsanB (GenBank accession No. AF224501), which is composed of 1740 bp encoding a protein consisting of 580 amino acid residues.
Its start codon is GTG at 100 bp position and stop codon is TGA at 1840-bp position. Database searching indicated that the
deduced protein ofsanB is homologous to the histidinol-phosphate aminotransferase inStreptomyces coelicolor with 31% identities and 47% positives. Gene disruption was performed to study the function ofsanB. It was found that disruptants ofsanB lost the ability to synthesize nikkomycin, which reveals thatsanB is a novel gene essential for nikkomycin biosynthesis.
Chinese Science Bulletin 04/2012; 45(23):2158-2162. · 1.32 Impact Factor
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ABSTRACT: Several genetically stable mutants blocked in nikkomycin biosynthesis were obtained after the slightly germinated spores ofStreptomyces ansochromogenes, a nikkomycin producer, were treated with ultra violet radiation. One of the mutants is the same in morpholotical differentiation
as the wild type strain and is designated as NBB19. A DNA library was constructed using plasmid pIJ702 as cloning vector,
NBB19 as cloning recipient. A 6 kb DNA fragment which can genetically complement NBB19 was cloned when screening the library
for antifungal activity. Sequence analysis showed that the 3 kbBgl II -Sal I fragment contains one complete ORF (ORF1) and one partial ORF (ORF2). ORF1 is designated assanA. sanA is 1 365 bp, encoding a protein consisting of 454 amino acid residues. Database searching indicated thatsanA is homologous to the hypothetical methyltransferase inPyrococcus horikoshii with 25% identities and 41% positives. Disruptant ofsanA lost the ability to synthesize nikkomycin. It indicated thatsanA is a novel gene which is essential for nikkomycin biosynthesis.
Science in China Series C Life Sciences 04/2012; 43(1):30-38. · 1.61 Impact Factor
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ABSTRACT: sawC, encoding a protein homologous to the WhiA sporulation regulator of Streptomyces coelicolor, was cloned from a fairly distantly related species, Streptomyces ansochromogenes. Disruption of sawC led to formation of aerial mycelium much longer than normal spore chains and with somewhat increased coiling, indicating that sawC plays an important role in the cessation of aerial hyphal growth similar to that of whiA, and that it has an effect on cell wall structure. However, complementation of sawC and whiA mutants with the same DNA fragment gave different results, which suggested that there may be some difference in regulation or function of WhiA/SawC between the two strains. S1 nuclease mapping identified one transcription start point of sawC. Using EGFP as a reporter, the spatial expression of sawC was shown to be confined to aerial hyphae. Computer-aided structural prediction analysis of SawC/WhiA proteins revealed the presence of a fold very similar to the endonuclease domain of PI-PfuI, raising the possibility that these proteins may interact with an intermediate in DNA repair or replication.
Archives of Microbiology 01/2008; 188(6):575-82. · 1.43 Impact Factor
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ABSTRACT: Previous studies revealed that two genes-sanU and sanV were associated with nikkomycin biosynthesis in Streptomyces ansochromogenes. A plasmid used to increase an extra copy of sanU and sanV was constructed and introduced into wild-type strain. HPLC results showed that nikkomycin production of recombinant strain was about 1.8 fold than that of wild-type strain. RT-PCR analysis indicated that the transcriptional level of sanU and sanV in this recombinant strain was about two folds than that of wild-type strain. The sanU and sanV were expressed in E. coli BL21 (DE3). SanU and SanV were purified individually. SanU and SanV assembled with coenzyme B12 to form a complete enzyme in vitro, which showed glutamate mutase activity. The glutamate mutase converted L-glutamate toL-threo-beta-Methylaspartic acid, and then l-threo-beta-Methylaspartic acid was probably deaminated to form 2-oxo-3-methylsuccinic acid to join biosynthetic pathway of the peptidyl moiety HPHT in S. ansochromogenes. SanU is the coenzyme B12-binding component and more than two folds of SanU are required for maximal enzyme activity. The optimal pH and temperature for the formed enzyme are 7.5-8.5 and 35-42 degrees C, respectively. Sulfhydryl compounds are important for activity of the reassembled enzyme.
Metabolic Engineering 06/2005; 7(3):165-73. · 5.61 Impact Factor
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ABSTRACT: The gene, sabR, encoding a receptor for gamma-butyrolactone, was cloned from the genomic DNA of Streptomyces ansochromogenes 7100. Its deduced protein shows strong homology to several gamma-butyrolactone-binding proteins in Streptomyces. Disruption of sabR retarded nikkomycin production in liquid media containing glucose or glycerol as carbon source. Sporulation of sabR disruption mutants was earlier than the parent strain on solid media with glucose or glycerol as carbon source. However, disruption of sabR had no effect on either nikkomycin production or sporulation on media containing mannitol as carbon source, suggesting that sabR is a pleiotropic regulatory gene that controls the onset of nikkomycin production and sporulation in S. ansochromogenes and is related to the utilization of carbon source.
Biotechnology Letters 10/2003; 25(18):1491-7. · 1.68 Impact Factor
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ABSTRACT: A 6.3-kb BamHI- BglII DNA fragment was cloned from cos20 by using chromosome walking strategy. It was partially sequenced with the result that there is a possible ORF of 1272 nucleotides. The ORF designated sanV was deposited in GenBank under accession no. AF469955. Database search indicated that the deduced protein of sanV shows 28% identity and 44% similarity over 405 amino acid residues to the large component (E) of glutamate mutases from Clostridium cochlearium. Gene disruption was performed to study the function of sanV. It was found that sanV disruptants exhibited much poorer inhibition to the test strain than the wild-type S. ansochromogenes 7100. Furthermore, HPLC analysis indicated that the sanV disruptants almost did not produce nikkomycins X and Z, whereas they accumulated new nikkomycins O(x) and O(z), which revealed that sanV is an important gene involved in the biosynthesis of the peptidyl moiety of nikkomycins.
Current Microbiology 07/2003; 46(6):403-7. · 1.82 Impact Factor
