Download MendeleyStructural Studies of Molybdopterin Synthase Provide Insights into its Catalytic Mechanism
Rudolph, M.J., Wuebbens, M.M., Turque, O., Rajagopalan, K.V., Schindelin, H.(2003) J Biol Chem 278: 14514-14522
- PubMed: 12571227
- DOI: https://doi.org/10.1074/jbc.M300449200
- Primary Citation of Related Structures:
1NVI, 1NVJ - PubMed Abstract:
Molybdenum cofactor biosynthesis is an evolutionarily conserved pathway present in eubacteria, archaea, and eukaryotes, including humans. Genetic deficiencies of enzymes involved in cofactor biosynthesis in humans lead to a severe and usually fatal disease. The molybdenum cofactor contains a tricyclic pyranopterin, termed molybdopterin, that bears the cis-dithiolene group responsible for molybdenum ligation. The dithiolene group of molybdopterin is generated by molybdopterin synthase, which consists of a large (MoaE) and small (MoaD) subunit. The crystal structure of molybdopterin synthase revealed a heterotetrameric enzyme in which the C terminus of each MoaD subunit is deeply inserted into a MoaE subunit to form the active site. In the activated form of the enzyme, the MoaD C terminus is present as a thiocarboxylate. The present study identified the position of the thiocarboxylate sulfur by exploiting the anomalous signal originating from the sulfur atom. The structure of molybdopterin synthase in a novel crystal form revealed a binding pocket for the terminal phosphate of molybdopterin, the product of the enzyme, and suggested a binding site for the pterin moiety present in precursor Z and molybdopterin. Finally, the crystal structure of the MoaE homodimer provides insights into the conformational changes accompanying binding of the MoaD subunit.
Organizational Affiliation:
Department of Biochemistry and Cell Biology, State University of New York at Stony Brook, 11794-5215, USA.
