Catalyzes the formation of dTDP-glucose, from dTTP and glucose 1-phosphate, as well as its pyrophosphorolysis. Is the first of four enzymes commited to biosynthesis of dTDP-L-rhamnose in S.typhimurium LT2. Is also able to convert non natural substrates such as a wide array of alpha-D-hexopyranosyl, deoxy-alpha-D-glucopyranosyl, aminodeoxy-alpha-D-hexopyranosyl and acetamidodeoxy-alpha-D-hexopyranosyl phosphates to their corresponding dTDP- and UDP-nucleotide sugars. alpha-D-glucose 1-phosphate + dTTP + H(+) = diphosphate + dTDP-alpha-D-glucose Binds 1 Mg(2+) ion per subunit. Carbohydrate biosynthesis; dTDP-L-rhamnose biosynthesis. Bacterial outer membrane biogenesis; LPS O-antigen biosynthesis. Homotetramer. Belongs to the glucose-1-phosphate thymidylyltransferase family. The position of the magnesium ion observed in the crystallographic structure is different from that observed in the structure of E.coli RmlA2 (RffH) and does not seem to correspond to the binding site for the catalytically essential magnesium ion. Therefore, we choose to propagate in the feature lines the positions found in the E.coli structure.