The Department of Chemistry presents Professor Kenneth D. Karlin as the 2017 Leallyn Burr Clapp lecturer. He will give the lecture on Thursday, April 13 and a colloquium the following day as part of Chemistry's Friday Colloquium Series.
Thursday, April 13, 2017
4:00 PM, Metcalf Research Building, Room 101
190 Thayer Street
Copper is a vital constituent of metalloprotein active sites, whose biological roles include electron shuttling and processing of small molecule nitrogen oxides or molecular oxygen. The biochemistry of copper surrounds its rich one-electron CuII/CuI redox chemistry. The presentation will include an overview of relevant protein chemistry with a focus on copper(II)-superoxide complexes derived from ligand-CuI/O2 reactions. Their structures, physical-spectroscopic and reactivity toward substrates with C–H or O–H bonds are of fundamental interest and will be described. The presentation will focus on ligand design and ligand systematic variations which strongly influence the CuI-O2 chemistry observed. An important experimental aspect is use of cryogenic solution handling of new Cun/O2 species.
Chemistry Colloquium: Toward a Deeper Understanding of O–O Reductive Cleavage in Heme-Copper Oxidases
Friday, April 14, 2017
4:00 PM, MacMillan Hall 115
167 Thayer Street
Heme-copper oxidases facilitate the four-electron four-proton reduction of dioxygen to water; this reaction couples to the biological ATP production. Our research goal is to contribute to a fundamental understanding of O2-reactivity at heme/Cu centers via examination of model systems. The synthesis of reduced (heme)FeIICuI(ligand) ensembles is described; their reactions with O2 gives high-spin (iron) peroxo-bridged FeIII-(O22-)-CuII(ligand) complexes whose structure depends on the Cu-chelating ligand. Conversion to low-spin analogues occurs by addition of an heme axial-ligand (B) giving (B)FeIII-(μ-1,2-O22–)-CuII(ligand) peroxo species. The nature of the Cu-ligation dictates the physical properties and subsequent reactivity of these assemblies. A recent study employs varying proton and electron sources leading to situations where Cu-O bond cleavage occurs releasing hydrogen peroxide, or biomimetic O–O reductive cleavage giving water takes place.
Kenneth D. Karlin is the Ira Remsen Professor of Chemistry and the current department Chair at Johns Hopkins University in Baltimore, Maryland, USA. He grew up in Palo Alto, California, and was educated at Stanford University (B.S. 1970) and at Columbia University, New York (Ph.D. 1975; Preceptor, S. J. Lippard). He was a N.A.T.O. postdoctoral fellow at Cambridge University in England before being appointed Assistant Professor of Chemistry at the State University of New York at Albany (SUNY Albany) in 1977. He moved to The Johns Hopkins University as Professor in 1990, where he was appointed as Ira Remsen Professor of Chemistry in 1999. Dr. Karlin is Editor-in-Chief of Progress in Inorganic Chemistry (John Wiley & Sons) and holds or has held advisory or administrative positions with the Society for Biological Inorganic Chemistry (SBIC), the Petroleum Research Fund (PRF) (of the American Chemical Society (ACS)) and the Division of Inorganic Chemistry (DIC) of the ACS, most recently as 2013 DIC Chair (elected)). He is also a Fellow of the American Association for the Advancement of Science and was elected as an ACS Fellow in 2014. For research accomplishments, he won a 2009 ACS National Award, the F. Albert Cotton Award in Synthetic Inorganic Chemistry. He has been Organizer/Chair of a number of international meetings on copper and/or bioinorganic chemistry, the 1998 Metals in Biology Gordon Research Conference and the 1989 International Conference on Bioinorganic Chemistry (ICBIC-4). Dr. Karlin’s bioinorganic research focuses on the design, synthesis and study of coordination complexes whose chemistry is relevant to biological processes, mainly metalloenzyme active site chemistry, involving copper and/or heme (porphyrin-iron) complexes and their chemistry with molecular oxygen, its reduced derivatives, and nitrogen oxide compounds.