Prof. Robert P. Hausinger Department of Chemistry Michigan State University Monday, April 8, 2019 - 11:15am Chemistry Building, Room 400 Inorganic Seminar CMS Seminar Lactic acid, a central metabolic intermediate of many cells, occurs as L- and D-isomers that are interconverted by lactate racemase. This enzyme from Lactobacillus plantarum is encoded by LarA and harbors a tethered nickel-pincer nucleotide (NPN) coenzyme derived from niacin. Synthesis of the enzyme-bound cofactor requires LarB, a carboxylase/hydrolase of nicotinic acid adenine dinucleotide (NaAD); LarE, a Mg·ATP-dependent sacrificial sulfur insertase; and LarC, a CTP-dependent nickel insertase or cyclometallase. This seminar will summarize recent studies related to NPN synthesis and function. References: Desguin B, T. Zhang, P. Soumillion, P. Hols, J. Hu, and R. P. Hausinger (2015) A tethered niacin-derived pincer complex with a nickel-carbon bond in lactate racemase. Science 349(6243):66–69. Rankin, J. A., R. C. Mauban, M. Fellner, B. Desguin, J. McCracken, J. Hu, S. A. Varganov, and R. P. Hausinger. 2018. Lactate racemase nickel-pincer cofactor operates by a proton-coupled hydride transfer mechanism. Biochemistry 57:3244-3251. Hausinger, R. P., B. Desguin, M. Fellner, J. A. Rankin, and J. Hu. 2018. Nickel-pincer nucleotide cofactor. Curr. Opin. Chem. Biol. 47:18-23. Hausinger, R. P. 2019. New metal cofactors and recent metallocofactor insights. Curr. Opin. Struct. Biol. 59:1-8.
