Tracking Down Biotransformation to the Genetic Level: Identification of a Highly Flexible Glycosyltransferase from Saccharothrix espanaensis

Abstract

e Saccharothrix espanaensis is a member of the order Actinomycetales. The genome of the strain has been sequenced recently, revealing 106 glycosyltransferase genes. In this paper, we report the detection of a glycosyltransferase from Saccharothrix espanaensis which is able to rhamnosylate different phenolic compounds targeting different positions of the molecules. The gene encoding the flexible glycosyltransferase is not located close to a natural product biosynthetic gene cluster. Therefore, the native function of this enzyme might be not the biosynthesis of a secondary metabolite but the glycosylation of internal and external natural products as part of a defense mechanism.

Glycosyltransferases: mechanisms and applications in natural product development

“…15 Asm25 together with Asm41 (glycosyl hydrolase) in the ansamitocin biosynthetic gene cluster was also speculated to exert homologous function with OleI. 214 Additionally, several other Gts have been identified or speculated to be MGTs (Table 4), such as GimA in a spiramycin producer (another MGT was proposed to exist but has not been identified), 215 Ses60310 which can use different NDP-sugars to rhamnosylate a series of phenolic compounds with a remarkable regioflexibility, 176 AcuGT3 with high similarity to MGT in aculeximycin biosynthesis gene cluster, 152 etc.…”

“…Moderate sugar flexibility Vancomycin analogues MtmGIII 261 Some sugar donor tolerance -NovM 262 Broad sugar flexibility A range of planar bicyclic aromatic compounds NypY 263 -Some aglycon flexibility NysDI 229 Some tolerance to aglycon structural diversity Stringent GDP-sugar specificity OleD a15 Some sugar flexibility Broad aglycon flexibility OleG2 264 Some sugar flexibility Some aglycon flexibility OleI 15 Some sugar flexibility Only glycosylates oleandomycin PegA 263 -Some aglycon flexibility RavGT 159 Broad sugar flexibility Coumarin-based polyketide derived backbone RebG 265 -A set of indolocarbazole surrogates Ses60310 176 Some sugar flexibility A variety of phenolic compounds SorF 266 Broad sugar flexibility -SpcG 178 Certain sugar flexibility -StaG 246 Certain sugar flexibility -StfG 267 Moderate sugar flexibility Stringent aglycon specificity Thus 218 Certain sugar flexibility Certain promiscuity towards peptide substrates TiaG1 & G2 182 Some sugar flexibility -TylMII 243 Certain sugar flexibility Structurally related aglycones UrdGT2 217 Certain sugar flexibility Certain aglycon flexibility VinC a 268 Utilize diverse NDP-sugars Structurally related and non-related compounds a Were utilized in an ''in vitro glycorandomization'' strategy to generate diverse glycosylated antibiotics.…”

Genome-Guided Discovery of Highly Oxygenated Aromatic Polyketides, Saccharothrixins D–M, from the Rare Marine Actinomycete Saccharothrix sp. D09

“…Bioinformatic analysis of the genome of D09 allowed us to identify three putative glycosyltransferases, which are homologous to Ses60310, a l -rhamnosyltransferase from Saccharothrix espanaensis DSM 44229 (Figure S11 and Table S5). This analysis also supported our proposal that the absolute configurations of the rhamnose residues in saccharothrixins could be α- l -rhamnose. Collectively, post-PKS modifications, especially the versatile oxidations, are critical for the structural diversity of 1 – 20 .…”

Functional Characterization of a Regiospecific Sugar-O-Methyltransferase fromNocardia

“…To produce methoxy-rhamnosylated derivatives using engineered E. coli , anthraquinone rhamnosyltransferase (7665) ( 33 ) from Saccharothrix espanaensis was cloned into pET-32a(+). E. coli S2 strain was generated by transforming pET32a(+)-7665(Am) CRISPRi-S1(Cm r ) and pCDFDuet-metK-thnM1(Sm) into an E. coli strain harboring the rhamnose cassette piBR181-tgs.dh.ep.kr.pgm2 glf glk (Km) ( 30 ).…”