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Structure and Reversible Pyran Formation in Molybdenum Pyranopterin Dithiolene Models of the Molybdenum Cofactor

Author:
Williams, Benjamin R., Fu, Yichun, Yap, Glenn P. A., Burgmayer, Sharon J. Nieter
Source:
Journal of the American Chemical Society 2012 v.134 no.48 pp. 19584-19587
ISSN:
1520-5126
Subject:
X-radiation, catalytic activity, crystallography, enzymes, ligands, models, molybdenum, nuclear magnetic resonance spectroscopy, tungsten
Abstract:
The syntheses and X-ray structures of two molybdenum pyranopterin dithiolene complexes in biologically relevant Mo(4+) and Mo(5+) states are reported. Crystallography reveals that these complexes possess a pyran ring formed through a spontaneous cyclization reaction of a dithiolene side-chain hydroxyl group at a CN bond of the pterin. NMR data on the Mo(4+) complex suggest that a reversible pyran ring cyclization occurs in solution. These results provide experimental evidence that the pyranopterin dithiolene ligand in molybdenum and tungsten enzymes could participate in catalysis through dynamic processes modulated by the protein.
Agid:
5387329