A new route to dTDP-6-deoxy-l-talose and dTDP-l-rhamnose: dTDP-l-rhamnose 4-epimerase in Burkholderia thailandensis

dTDP-l-rhamnose (dTDP-Rha)-synthesizing dTDP-6-deoxy-l-lyxo-4-hexulose reductase (4-KR) and dTDP-Rha 4-epimerase were characterized from Burkholderia thailandensis E264 by utilizing rmlDBth (BTH_I1472) and wbiBBth (BTH_I1476), respectively. Incubation of the recombinant WbiBBth with RmlA/RmlB/RmlC/Tal, which has previously been shown to generate dTDP-6-deoxy-l-talose (dTDP-6dTal) from α-d-glucose-1-phosphate, dTTP, and NADPH, produced dTDP-Rha. 1H NMR measurements confirmed that both RmlA/RmlB/RmlC/Tal/WbiBBth and RmlA/RmlB/RmlC/RmlD produced dTDP-Rha. WbiBBth alone produced dTDP-Rha when incubated with dTDP-6dTal. This is the first report to demonstrate epimerase activity interconverting between dTDP-Rha and dTDP-6dTal.

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