Isolation and sequencing of glycosyltransferase gene and UDP-glucose dehydrogenase gene that are located on a gene cluster involved in a new exopolysaccharide biosynthesis in Streptomyces.
Streptomyces sp. 139 produces a new exopolysaccharide (EPS) that shows anti-rheumatic arthritis activity in vivo. To investigate the gene cluster involved in EPS biosynthesis, degenerate primers were designed to amplify an internal fragment of the priming glycosyltransferase gene that catalyzes the first step in EPS biosynthesis. Using this PCR product as probe, positive cosmid clones were selected from a genomic library of Streptomyces sp. 139, which led to the localization of ste (Streptomyces eps) gene cluster on the approximately 65-kb chromosomal region. A 4.0-kb Bam HI fragment from all positive cosmids that hybridized to this probe was sequenced, which revealed two genes encoding the priming glycosyltransferase and UDP-glucose dehydrogenase. The putative priming glycosyltransferase is suggested to catalyze the first step in the biosynthesis of EPS repeating unit and UDP-glucose dehydrogenase is suggested to convert UDP-glucose into UDP-glucuronic acid involved in nucleotide sugar precursor synthesis of EPS biosynthesis.
Wang
Lingyan
L
Institute of Medicinal Biotechnology, Chinese Academy of Medical Sciences, Tiantan Xili 1, Beijing 100050, People's Republic of China.
Li
Shitao
S
Li
Yuan
Y
D000595:Amino Acid Sequence; D003360:Cosmids; D017931:DNA Primers / Q000378:metabolism; D015723:Gene Library; D016695:Glycosyltransferases / Q000235:genetics* / Q000302:isolation & purification*; D008957:Models, Genetic; D008969:Molecular Sequence Data; D005810:Multigene Family; D016133:Polymerase Chain Reaction; D011134:Polysaccharides / Q000096:biosynthesis*; D013302:Streptomyces / Q000201:enzymology* / Q000235:genetics; D014533:Uridine Diphosphate Glucose Dehydrogenase / Q000235:genetics* / Q000302:isolation & purification*
D017931:DNA Primers; D011134:Polysaccharides; D014533:Uridine Diphosphate Glucose Dehydrogenase; D016695:Glycosyltransferases