Involved in the biosynthesis of the 2,3,6-trideoxysugar L-epivancosamine, the terminal sugar added to the aglycone scaffold of chloroeremomycin, a member of the glycopeptide antibiotics vancomycin family. Catalyzes the removal of the hydroxyl group at position C-2 of the hexose ring of dTDP-4-dehydro-6-deoxy-alpha-D-glucopyranose, and the oxidation of the hydroxyl group at position C-3 to form a carbonyl functionality. The product of the reaction, dTDP-2,6-dideoxy-D-glycero-hex-2-enos-4-ulose, is a highly unstable diketosugar, which spontaneously forms dTDP-3,4-didehydro-2,6-dideoxy-alpha-D-glucose. dTDP-4-dehydro-6-deoxy-alpha-D-glucose = dTDP-3,4-didehydro-2,6-dideoxy-alpha-D-glucose + H2O Antibiotic biosynthesis. Homodimer. The mutant Ala-381 is used to improve the quality of the crystals. Two binding sites (pockets A and B) for the dTDP-sugar ligands have been identified in each subunit. It seems that pocket A represents the active site and pocket B is a vestige of the gene duplication event. Belongs to the hexose 2,3-dehydratase family.