Tetrahydrofolates (THFs) are cofactors that donate or accept single carbon units in metabolic processes. 5,10-methenyltetrahydrofolate synthetase (MTHFS) is the only known enzyme to use 5-formylTHF. MTHFS catalyses tbe conversion of 5-formyTHF to 5,10-methenylTHF coupled to the hydrolysis of ATP to ADP in the presence of magnesium. In solution, MTHFS exists 50% dimeric form, 50% in monomeric form.
Defined by 3 residues: ARG:A-140 [auth A-115]ASP:A-149 [auth A-124]ASP:A-179 [auth A-154]