Bryn Mawr College

Sharon J. Nieter Burgmayer

Within the area of bioinorganic chemistry, the attention of my research group is focused on those metalloenzymes that require a pterin cofactor. The metals represented in this group are iron, copper, molybdenum, and tungsten. The pterin portion is a nitrogen heterocycle related to the familiar nucleic acid guanine. These enzymes are widely distributed throughout Nature where they performorganic redox reactions, primarily hydroxylations, that are critical to the health of the organism. Both the metal and the pterin have a rich and complicated redox reactivity in the absence of the protein coat and this fact underlies many of our projects concerned with questions of how metals and pterins behave in redox reactions, both individually and with each other. The specific tether that connects the molybdenumor tungsten atomto the pterin cofactor is a dithiolene; an illustration of the molybdenumcofactor of the bacterial enzyme DMSO reductase is shown below opposite one of our target model complexes.

A second set of projects involves the development of syntheses for producing such target model complexes having pterin-dithiolene ligands coordinated to molybdenum. These projects involve both inorganic and organic syntheses, many of which are performed under inert atmosphere environments. The synthetic products and their chemical reactivity are studied by spectroscopic analysis, electrochemical characterization, kinetic studies, structure determination by x-ray crystallography, and molecular modeling. Routine spectroscopic techniques such as FT-NMR, FT-IR, UV-vis, and fluorescence are conducted in the Bryn Mawr chemistry department. Certain projects require other techniques, such as EPR or XPS, that are accomplished through collaborations with researchers at other institutions.

Recent Publications

“DNA Binding by Ru(II)-bis(bipyridine)-Pteridinyl Complexes”
Shannon Dalton, Samantha Glazier, Belinda Leung*, Sanda Win*, Sharon J. Nieter Burgmayer, Journal of Biological Inorganic Chemistry, 2008, in press

"Synthesis, Characterization, and Spectroscopy of Model Molybdopterin Complexes"
Sharon J. Nieter Burgmayer, Mary Kim*, Rebecca Petit*, Amy Rothkopf*, Alison Kim*, Shadia BelHamdounia*, Ying Hou*, Arpad Somogyi, Diana Habel-Rodriguez, Antonio Williams, Martin L. Kirk, Journal of Inorganic Biochemistry, 2007, 101, 1601-1616.

 "Redox Reactions of the Pyranopterin System of the Molybdenum Cofactor"
Sharon J. Nieter Burgmayer, Dori L. Pearsall, Shannon Blaney*, Eva Moore*, Calies Sauk-Schubert*
Journal of Biological Inorganic Chemistry, 2004, 9, 59.

 "Dithiolenes in Biology "
Sharon J. Nieter Burgmayer, in Progress in Inorganic Chemistry, Vol. 52, Stiefel, E. I., Ed.; Wiley, N. Y. 2004.

 “Molybdenum Enzymes/Models"
Sharon J. Nieter Burgmayer in Encyclopedia of Catalysis, Horvath, I. T., Ed.; Wiley & Sons, NY, 2002. 

 “Models for the Pyranopterin-Containing Molybdenum and Tungsten Cofactors”
Berthold Fischer and Sharon J. Nieter Burgmayer in Metal Ions in Biological Systems, Vol. 39, Sigel, A. and Sigel   H., Eds.; Marcel Dekker, N. Y., 2002, pp 265-305.