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Physical Chemistry Seminar 228: Douglas Rees

Physical, Physical Chemistry Seminar

March 11, 2024 4:00 pm - 5:00 pm
Speaker Prof. Douglas Rees


Prof. Doug Rees Flyer

Talk Title: Nitrogenase: Beyond the Resting State

Abstract: The enzyme nitrogenase has the remarkable ability to catalyze the reduction of dinitrogen to ammonia to under physiological conditions. The mechanistic questions related to how nitrogenase overcomes the kinetic stability of the NN triple bond to fix dinitrogen under ambient conditions have intrigued chemists for the past century. We have applied a structure-based approach to examine how nitrogenase uses iron-sulfur metalloclusters and ATP-dependent electron transfer to reduce dinitrogen and other substrates. A puzzling feature of the nitrogenase mechanism has been how to reconcile the relative stability of the FeMo-cofactor with the reactivity towards dinitrogen. Our studies have established that binding of ligands to nitrogenase under turnover conditions can be accompanied by the reversible displacement and rearrangements of sulfurs in the catalytic FeMo-cofactor; these rearrangements may provide clues how the active site is activated during the catalytic cycle. The complementary strengths of X-ray and electron scattering are being used to illuminate the structural foundations of this process.

Prof. Douglas Rees

Physical, Physical Chemistry Seminar

Roscoe Gilkey Dickinson Professor of Chemistry, Caltech