Scheme 2. Entry point into TDP-deoxysugar secondary metabolism in bacteria.
Following thymidylylation of α-d-glucose-1-phosphate (17) by a thymidylyltransferase, a TDP-glucose-4,6-dehydratase enzyme catalyzes the conversion of TDP-d-glucose (20) to TDP-4-keto-6-deoxy-α-d-glucose (21) in the committed step to TDP-deoxysugar biosynthesis.