The NDP-sugar co-substrate concentration and the enzyme expression level influence the substrate specificity of glycosyltransferases: cloning and characterization of deoxysugar biosynthetic genes of the urdamycin biosynthetic gene cluster

Abstract

Analysis of deoxysugar biosynthetic genes of the urdamycin biosynthetic gene cluster revealed a widely common biosynthetic pathway leading to D-olivose and L-rhodinose. Several enzymes responsible for specific steps of this pathway could be assigned. The pathway had to be modified compared to earlier suggestions. Two glycosyltransferases normally involved in the C-glycosyltransfer of D-olivose at the 9-position (UrdGT2) and in conversion of 100-2 to urdamycin G (UrdGT1c) show relaxed substrate specificity for their activated deoxysugar co-substrate and their alcohol substrate, respectively. They can transfer activated D-rhodinose (instead of D-olivose) to the 9-position, and attach L-rhodinose to the 4A-position normally occupied by a D-olivose unit, respectively.

Generation of New Landomycins with Altered Saccharide Patterns through Over‐expression of the Glycosyltransferase Gene lanGT3 in the Biosynthetic Gene Cluster of Landomycin A in Streptomyces cyanogenus S‐136

“…Note that we previously reported the accumulation of novel urdamycin analogues with altered saccharide patterns after over-expressing glycosyltransferase UrdGT1c in the urdamycin producer, S. fradiae Tü2717. [19] The minor compound LaI, with only one olivose attached to the aglycon moiety, was the first ever monosaccharidal landomycin produced by a S. cyanogenus strain, after its 11-deoxy analogue LaH (11-deoxy-LaI) was previously generated in a S. globisporus mutant. [10] While the accumulation of the tetrasaccharide 3 was anticipated and appeared to be an obvious result of the over-expression of LanGT3, the moderate accumulation of the monosaccharide 5 in S. cyanogenus (lanGT3) seemed surprising.…”

Biosynthetic Gene Cluster of Simocyclinone, a Natural Multihybrid Antibiotic

“…Computer-based sequence analysis revealed that simB1, simB2, simB3, simB4, and simB5 are involved in the biosynthesis of dTDP-D-olivose. In the case of simB4, simB5, and simB7, again, genes involved in the biosynthesis of urdamycin A (15) and landomycin A (54) are most similar. In contrast, gene products of simB1 (59), simB2 (26), and simB3 (50) showed high sequence similarities to deoxysugar biosynthetic genes from other clusters.…”

DNA Sequencing and Transcriptional Analysis of the Kasugamycin Biosynthetic Gene Cluster from Streptomyces kasugaensis M338-M1

“…The deduced KasR protein (399 amino acids, M r of 42,562, pI of 6.06) showed significant similarity to hexose C-3 dehydrases which are involved in 3-deoxygenation of deoxysugar moieties of some secondary metabolites. Homology analysis for KasR revealed similarity with LanQ [21], an NDP-hexose 3,4-dehydratase involved in landomycin biosynthesis in Streptomyces cyanogenus (38% identity); RdmI [22], a hexose C-3 dehydratase involved in rhodomycin biosynthesis in Streptomyces purpurascens (37% identity); UrdQ [23], an NDP-hexose 3,4-dehydratase involved in the formation of the L-rhodinose moiety of urdamycin in Streptomyces fradiae (37% identity); AscC [24], and a CDP-4-keto-6-deoxy-D-glucose-3-dehydrase involved in ascarylose biosynthesis in Yersinia pseudotuberculosis (36% identity). These enzymes are dependent on pyridoxamine 5Ј-phosphate (PMP) and contain an ironsulfur cluster.…”