09/18/18 - 9:45 AM to 10:45 AM
Kolthoff Lectureship #1: Professor John T. Groves
Izaak M. Kolthoff Lectureship in Chemistry
Watching the protons in C-H bond cleavage by metalloenzymes and metalloporphyrins
Nature has evolved a variety of remarkably efficient metalloenzymes for the selective oxygenation of even the most unreactive C–H bonds. Copper-containing particulate methane monooxygenases (pMMO), and the non-heme diiron enzymes sMMO and AlkB allow microorganisms to grow on natural gas and petroleum as their sole sources of carbon. Cytochrome P450s and fungal peroxygenases (APO) are heme-thiolate enzymes that generate an oxoiron(IV)-porphyrin π-radical cation (compound I) as the highly reactive intermediate that is able to break strong C-H bonds. Non-heme iron proteins such as TauD and SyrB2 break strong C–H bonds using a ferryl species, Fe(IV)=O. By distinct contrast, lipoxygenases employ hydroxoiron(III) or hydroxomanganese(III) intermediates to activate allylic C–H bonds. APO compound II [Cys-Fe(IV)-OH] is also reactive toward C–H bonds. In this lecture, I will discuss recent results from our lab in the areas of biomimetic metalloporphyrin catalysts and those of novel, heme-thiolate APO proteins with active sites similar to that of cytochrome P450. Particular emphasis will be on C–H cleavage events that have little or no driving force, focusing attention instead on electronic and structural features that affect intrinsic reaction barriers.
- Hongxin Gao and John T. Groves, Fast Hydrogen Atom Abstraction by a Hydroxo Iron(III) Porphyrazine, J. Am. Chem. Soc. 2017, 139, 3938-3941.
- Xiongyi Huang and John T. Groves, Beyond ferryl-mediated hydroxylation: 40 years of the rebound mechanism and C-H activation, J. Biol. Inorg. Chem. 2017, 22, 185–207.
- Xiongyi Huang and John T. Groves, Oxygen activation and radical transformations in heme proteins and metalloporphyrins, Chem. Rev. 2018, 118, 2491−2553
There will be a reception for Professor Groves from 5 p.m. to 6:30 p.m. Tuesday, Sept. 18, in Conference Rooms ABC, 4th floor of the Coffman Memorial Union (Campus Club).
Professor Groves’ research program is at the interface of organic, inorganic, and biological chemistry. Current efforts focus on the design of new, biomimetic catalysts and the molecular mechanisms of these processes, the design and assembly of large scale membrane-protein-small molecule constructs, studies of host-pathogen interactions related to iron acquisition by small molecule siderophores, and molecular probes of the role of peroxynitrite in biological systems.
Professor Groves received an undergraduate degree in chemistry at the Massachusetts Institute of Technology, where he worked with Frederick Greene. In 1965, he began his doctoral studies under the direction of Professor Ronald Breslow at Columbia University. Upon receiving his doctorate, Groves began his independent research career at the University of Michigan, in 1969. In 1985, he moved to Princeton University where he is Hugh Stott Taylor Chair of Chemistry. Groves is an award-winning inorganic chemist, receiving numerous accolades, including the American Chemical Society National Award in Inorganic Chemistry and the Sigma-Aldrich Award in Inorganic Chemistry. He is a member of the National Academy of Sciences, the American Academy of Arts and Sciences, and a Fellow of the Royal Society of Chemistry.
Kolthoff Lectureship in Chemistry
Izaak Maurits Kolthoff was born on February 11, 1894, in Almelo, Holland. He died on March 4, 1993, in St. Paul, Minnesota. In 1911, he entered the University of Utrecht, Holland. He published his first paper on acid titrations in 1915. On the basis of his world-renowned reputation, he was invited to join the faculty of the University of Minnesota’s Department of Chemistry in 1927. By the time of his retirement from the University in 1962, he had published approximately 800 papers. He continued to publish approximately 150 more papers until his health failed. His research, covering approximately a dozen areas of chemistry, was recognized by many medals and memberships in learned societies throughout the world, including the National Academy of Sciences and the Nichols Medal of the American Chemical Society. Best known to the general public is his work on synthetic rubber. During World War II, the government established a comprehensive research program at major industrial companies and several universities, including Minnesota. Kolthoff quickly assembled a large research group and made major contributions to the program. Many of Kolthoff’s graduate students went on to successful careers in industry and academic life and, in turn, trained many more. In 1982, it was estimated that approximately 1,100 Ph.D. holders could trace their scientific roots to Kolthoff. When the American Chemical Society inaugurated an award for excellence in 1983, he was the first recipient.