Sugar N-formyltransferase that catalyzes the conversion of dTDP-4-amino-4,6-dideoxyglucose into dTDP-4-formamido-4,6-dideoxyglucose using N(10)-formyltetrahydrofolate as the carbon source (PubMed:28665588). Plays a role in virulence (PubMed:12368431). Has no activity on dTDP-3-amino-3,6-dideoxyglucose, dTDP-3-amino-3,6-dideoxygalactose, UDP-4-amino-4-deoxyarabinose, and GDP-4-amino-4,6-dideoxymannose (PubMed:28665588). (6S)-10-formyltetrahydrofolate + dTDP-4-amino-4,6-dideoxy-alpha-D-glucose = (6S)-5,6,7,8-tetrahydrofolate + dTDP-4-formamido-4,6-dideoxy-alpha-D-glucose + H(+) kcat is 0.9 sec(-1). Homodimer. Mice infected with M.tuberculosis H37Rv mutants for Rv3404c present a highly significant increase in their survival time as compared with mice infected with the parental strain. Was identified as a high-confidence drug target. Belongs to the dTDP-Qui4N formyltransferase family.