<p> Synonym: dTDP-D-glucose synthase </p> <p> This group of proteins comprises a tightly conserved but broadly distributed subfamily (here designated as short form) of known and putative bacterial glucose-1-phosphate thymidylyltransferases (<db_xref db="EC" dbkey="2.7.7.24"/>). It iswell characterised in several species as the first of four enzymes involved in the biosynthesis of dTDP-L-rhamnose, a cell wall constituent and a feedback inhibitor of the enzyme. The enzyme is active as a homotetramer.<reaction> dTTP + alpha-D-glucose 1-phosphate = diphosphate + dTDP-glucose </reaction> </p><p> The family of known and putative glucose-1-phosphate thymidyltransferases shows a deep split into a short form described by this entry and a long form (<db_xref db="TIGRFAMs" dbkey="TIGR01208"/>). The homotetrameric short form is found in numerous bacterial species that incorporate dTDP-L-rhamnose, which it helps synthesize, into the cell wall. It is subject to feedback inhibition. The long form, in contrast, is found in many species for which it serves as a sugar-activating enzyme for antibiotic biosynthesis and or other, unknown pathways, and in which dTDP-L-rhamnose is not necessarily produced.</p>