The mononuclear molybdenum and tungsten enzymes function to catalyze the reduction and oxidation of a wide variety of substrates including sulfite, nitrate, DMSO, xanthine, and aromatic hydrocarbons. A common theme of the enzyme active sites is a complex electronic structure that derives from covalent bonding interactions between the metal site and the pyranopterin dithiolene. In order to gain insight into the complex metal-dithiolene interplay in the enzymes, we have used a combination of electronic absorption, magnetic circular dichroism, electron paramagnetic resonance, and resonance Raman spectroscopies to probe the electronic structure of metallo-dithiolene complexes as a function of electronic configuration.  The spectroscopic studies have been used to evaluate the results of theoretical and bonding calculations.  We will discuss the results of these studies in the context of how low-symmetry metal-dithiolene distortions contribute to redox potential modulation and superexchange pathways for electron transfer regeneration of the catalytically competent active sites.

Spectroscopic and computational studies of mononuclear molybdenum and tungsten enzymes: Links between electronic structure and enzyme function

243rd National Meeting (2012)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.