In vitro synthesis of molybdopterin from precursor Z using purified converting factor : role of protein-bound sulfur in formation of the dithiolene

摘要: The pterin component of the molybdenum cofactor, termed molybdopterin, is synthesized in Escherichia coli by enzymes encoded at chl loci. A late step biosynthetic pathway, conversion a molybdopterin intermediate, precursor Z, to requires activity two-subunit protein, converting factor. Precursor Z has many features but lacks dithiolene function essential for ligation. Conversion accomplished transfer sulfur produce dithiolene. present study describes an vitro system biosynthesis comprised purified and It established that these components are sufficient yield identified its characteristic products, Form A, B, dicarboxamidomethylmolybdopterin. Under conditions excess, formation was stoichiometric with factor, as would be expected absence sulfur-regenerating system. labile product reaction, remained associated factor large subunit. These results establish source suggest vivo novel cycle must resupply