Biochemical characterization of recombinant guaA-encoded guanosine monophosphate synthetase (EC 6.3.5.2) from Mycobacterium tuberculosis H37Rv strain

► The Mycobacterium tuberculosis guaA gene encodes a homodimeric GMP synthetase (MtGMPS). ► The two-domain type MtGMPS exhibits positive homotropic cooperativity for XMP and NH4+. ► Mg2+ saturation curve is sigmoidal and there may be an additional binding site for this metal. ► Activity of ATPPase domain is independent of GATase domain. ► Substrate binding is random and PPi is the last product released.