Mechanisms and pathways from recent deoxysugar biosynthesis research

Characterization of the O‐antigen gene clusters of Yersinia pseudotuberculosis and the cryptic O‐antigen gene cluster of Yersinia pestis shows that the plague bacillus is most closely related to and has evolved from Y. pseudotuberculosis serotype O:1b

“…Furthermore, both the predicted mannosyltransferases, WbyJ and WbyK, seemed to be functional in Y. pestis , whereas the wbyI gene coding for a putative glycosyltransferase was inactivated. Inactivation of the CDP‐paratose biosynthesis before the DdhB stage is also logical, as the first committed step in the Ddh pathway is catalysed by DdhB (Johnson and Liu, 1998); the glucose‐1‐P pool will not be depleted.…”

Structural diversity inSalmonellaO antigens and its genetic basis

“…It is worth noting that in addition to Salmonella O30, O35, O50, and O62, there are 11 Salmonella O antigens that cross-react serologically with one or more E. coli O antigens (Orskov et al, 1977), and 7 of them (Salmonella (Johnson & Liu, 1998). ManA, phosphomannose isomerase; ManB, phosphomannomutase; ManC, mannose-1-phosphate guanylyltransferase (Samuel & Reeves, 2003); Gmd, GDP-mannose 4,6-dehydratase (Somoza et al, 2000;Kneidinger et al, 2001); ColA, GDP-4-keto-6-deoxy-D-mannose 3-dehydrase (Alam et al, 2004); ColB, GDP-colitose synthase (Alam et al, 2004); PerA, GDP-perosamine synthetase (Zhao et al, 2007;Albermann & Beuttler, 2008); PerB, GDP-perosamine N-acetyltransferase (Albermann & Beuttler, 2008); Rib, ribulose 5-phosphate reductase/CDP-ribitol pyrophosphorylase (Follens et al, 1999); RmlA, glucose-1-phosphate thymidylyltransferase (Zuccotti et al, 2001); RmlB, dTDP-D-glucose 4,6-dehydratase (Allard et al, 2001); FdtA, dTDP-6-deoxy-hex-4-ulose isomerase; FdtB, dTDP-6-deoxy-D-xylo-hex-3-ulose aminase; FdtC, dTDP-D-Fuc3N acetylase (Pfoestl et al, 2003); QdtA, dTDP-4-oxo-6-deoxy-Dglucose 3,4-oxoisomerase; QdtB, dTDP-3-oxo-6-deoxy-D-glucose aminase; QdtC, dTDP-D-Qui3N acetylase (Pfostl et al, 2008); DdhA, glucose-1phosphate cytidylyltransferase; DdhB, CDP-glucose 4,6-dehydratase; DdhC, CDP-4-keto-6-deoxy-D-glucose 3-dehydrase; DdhD, CDP-6-deoxy-D 3,4glucoseen reductase (Johnson & Liu, 1998;Samuel & Reeves, 2003); Abe, CDP-abequose synthase (Hallis et al, 1998); Prt, CDP-paratose synthase (Hallis et al, 1998); Tyv, CDP-Par 2-epimerase (Koropatkin et al, 2003); FnlA, 4,6-dehydratase/5-epimerase; FnlB, 3-epimerase/ reductase; FnlC, C2 epimerase (Mulrooney et al, 2005);WbuX, aminotransferase (King et al, 2008); NnaA, GlcNAc-2-epimerase; NnaB, Neu5Ac condensing enzyme; NnaC, CMP-Neu5Ac synthetase (Annunziato et al, 1995); Esb1, C6 dehydratase/C5 epimerase; Esb2, aminotransferase; Esb3, acetyltransferase; Esb4, nucleotidase; Esb5, condensase; Esb6, cytidylyltransferase. a The enzyme is encoded by the gene, which is not located in the O-antigen gene cluster.…”

Insights about the biosynthesis of the avermectin deoxysugar L-oleandrose through heterologous expression of Streptomyces avermitilis deoxysugar genes in Streptomyces lividans

“…They propose that TDP-4-keto-6-deoxyglucose undergoes epimerization by EryBVII, followed by 2,3-dehydration (EryBVI) and reduction (EryBII), C-methyl transfer (EryBIII) and ¢nally reduction of the 4-keto group by EryBIV to give TDP-Lmycarose. Although the TDP group may not be the activating nucleotide in all such pathways [5,6], Schulman and coworkers have unambiguously established, by isolation and bioconversion experiments, that avermectin biosynthesis utilizes TDP-L-oleandrose [24]. Its attachment to the avermectin aglycone is catalyzed by the glycosyltransferase AvrB/AveBI while the genes eryBV and tylCV govern the corresponding steps involving TDP-L-mycarose in the erythromycin [15^18] and tylosin [20] pathways.…”