University of Iowa - Amnon Kohen






	Selected Recent Publications- Amnon Kohen Mishanina, T.V., Koehn, E.M., Conrad, J.A., Palfey, B., Lesley, S.A., and Kohen, A., Flavin-Dependent Thymidylate Synthase: Trapping of a Reaction Intermediate, J. Am. Chem. Soc., Accepted for publication Jan 30, 2012. Stojkoviç, V., Perissinotti, L., Willmer, D., Benkovic, S., and Kohen, A., Effects of the donor acceptor distance and dynamics on hydride tunneling in the dihydrofolate reductase catalyzed reaction, J. Am. Chem. Soc., 2012, 134, 1738-1745. Saeed, M., Tewson, T.J., Erdahl, C.E., and Kohen, A.,* A fast chemo-enzymatic synthesis of [11C]-N5,N10-methylenetetrahydrofolate as a potential PET tracer for proliferating cells, Nucl. Med. Biol., Accepted for publication Dec. 5, 2011. Oyeyemi, O.A., Sours, K.M., Lee, T., Kohen, A., Resing, K.A., Ahn, N.G., and Klinman, J.P.,* Comparative Hydrogen-Deuterium Exchange for a Mesophilic vs Thermophilic Dihydrofolate Reductase at 25 °C: Identification of a Single Active Site Region with Enhanced Flexibility in the Mesophilic Protein, Biochemistry, 2011, 50, 8251-8260. Mishanina, T.V., Koehn, E., and Kohen, A.,* Mechanisms and inhibition of uracil methylating enzymes, Bioorg. Chem. Published on-line Nov. 29, 2011 (Review) Dutta, S., Li, Y-L., Rock, W., Houtman, J.C., Kohen, A., and Cheatum, C.M.,* 3-Picolyl Azide Adenine Dinucleotide as a Probe of Femtosecond to Picosecond Enzyme Dynamics, J. Phys. Chem. B., 2012, 116, 542-548. Wang, Z., Roston, D., and Kohen, A.,* "Experimental and theoretical studies of enzyme-catalyzed hydrogen transfer reactions", in Advances in Protein Chemistry and Structural Biology (in the thematic volume "Structural and Experimental Enzymology - bringing experiments and computations together"), C. Christov and T. Karabencheva, Ed.. Elsevier. Accepted for publication Nov 25, 2011 Doron, D., Major, D.T.,* Kohen, A., Thiel, W., and Wu, X., Hybrid Quantum and Classical Simulations of the Dihydrofolate Reductase Catalyzed Hydride Transfer Reaction on an Accurate Semi-Empirical Potential Energy Surface, J. Chem. Theory Comput., 2011, 7, 3420–3437 Ditzler, L., Sen, A., Gannon, M., Kohen, A.,* and Tivanski, A.,* Self-assembled enzymatic monolayer directly bound to a gold surface: Activity and molecular recognition force spectroscopy studies, J. Am. Chem. Soc. (Communication), 2011,133, 13284-13287. Saeed, M., Sheff, D, and Kohen, A., A novel positron emission tomography tracer distinguishes normal from cancerous cells, J. Biol. Chem., 2011, 286, 33872-33878. Dutta, S., Rock, W., Cook, R. J. Kohen, A., and Cheatum C. M., Two-dimensional infrared spectroscopy of azido-nicotinamide adenine dinucleotide in water, J. Chem. Phys., 2011, 135, 055106. (Published on line Aug 5, 2011) Sen, A., Yahasiri, A., and Kohen, A., Triple isotopic labeling and kinetic isotope effects: a sensitive and accurate method for exposing H-transfer steps in enzymatic systems, Biochemistry, 2011, 50, 6462–6468. Kanaan, N., Ferrer, S., Martí, S, Garcia-Viloca, M., and Kohen, A., and Moliner, V., Temperature Dependence of the Kinetic Isotope Effects in Thymidylate Synthase, A Theoretical Study, J. Am. Chem. Soc., 2011, 133, 6692-6702. Kohen, A.,* Roston, D., Stojkovic, V., and Wang, Z, "Kinetic Isotope Effect in Enzymology", in Encyclopedia of Anlytical Chemistry, R. A. Meyers, Ed.; John Wiley & Sons, Ltd: Chichester, UK, 2011; Vol. S1-S3, pp 77-99, ISBN: (978-0-470-97333-2). Stojkovic, V., Perissinotti, L.L., Lee, J., Benkovic, S.J., and Kohen, A., The effect of active-site isoleucine to alanine mutation on the DHFR catalyzed hydride-transfer, Chem. Commun., 2010, 46, 8974-8976 (Communication). Bandaria, J.N., Dutta, S., Nydegger, M.W., Rock, W., Kohen, A., and Cheatum, C.M., Characterizing the dynamics of functionally relevant complexes of formate dehydrogenase, Proc. Natl. Acad. Sci. USA 2010, 107, 17974-17979. Dutta, S., Cook, R.J., Houtman, J.C.D., Kohen, A., and Cheatum, C.M., Characterization of azo-NAD to assess its potential as a two-dimensional infrared probe of enzyme dynamics, Anal. Biochem., 2010, 407, 241-246. Sen, A., and Kohen, A., Enzymatic tunneling and kinetic isotope effects: chemistry at the crossroads, J. Phys. Org. Chem.* 2010, 23, 613-619 (invited review for a special issue entitled "Symposium in Print on Tunneling") Wang, Z. and Kohen, A., Thymidylate Synthase Catalyzed H-transfers: Two Chapters in One Tale, J. Am. Chem. Soc.* 2010, 132, 9820-9825. Roston, D. and Kohen, A., Elusive Transition State of Alcohol Dehydrogenase Unveiled , Proc. Natl. Acad. Sci. USA* 2010, 107, 9572-9577 Koehn, E.; Kohen, A., “Flavin-dependent thymidylate synthase: A novel pathway towards thymine”, Archiv. Biochem. Biophys.* 2010, 493, 96-102. Yahashiri, A.; Nimrod, G.; Ben-Tal, N.; Howell, E.E.; Kohen, A., “Effect of electrostatic shielding on H-tunneling in R67 dihydrofolate”, ChemBioChem, 2009, 10, 2620-2623. Hill, S.E., Bandaria, J.N., Fox, M., Vanderah, E., Kohen, A., and Cheatum, C.M., “Exploring the Molecular Origins of Protein Dynamics in the Active Site of Human Carbonic Anhydrase II”, J. Phys Chem. B. 2009, 113, 11505 - 11510. Yahashiri, A., Sen, A., and Kohen, A., “Microscale synthesis and kinetic isotope effect analysis of (4R)-[Ad-¹⁴C,4-²H] NADPH and (4R)-[Ad-³H,4-²H] NADPH”, J. Labeled Comp. Radiopharma, 2009, 52, 463-466. Bandaria, J., Cheatum, C.M., and Kohen, A., “Examination Examination of enzymatic H-tunneling through kinetics and dynamics”, J. Am. Chem. Soc., 2009, 131, 10151-10155. Koehn, E.; Fleischmann, T.; Conrad, J.A.; Palfey, B.; Lesley, S.A.; Kohen, A., “An unusual mechanism of thymidylate biosynthesis in organisms containing the thyX gene” Nature* 2009, 458 919-923. Wang, Z., Chernyshev, A., Koehn, E.M., Manuel, A., Lesley, S.A., and Kohen, A., “Oxidase Activity of a Flavin-Dependent Thymidylate Synthase”, FEBS J., 2009, 276, 2801–2810. Stojkovic, V.; Kohen A., “Enzymatic H-transfers: Quantum Tunneling and Coupled Motion from Kinetic Isotope Effect Studies”, Isr. J. Chem. 2009, 49, 163-173 (Invited Review). Sen, A., and Kohen, A., “Quantum Effects in Enzyme Kinetics”, in Quantum Tunneling in Enzyme Catalyzed Reactions, Allemann, R. and Scrutton, N., Eds, Royal Society of Chemistry, London, UK, 2009, Ch. 7, pp.161-181. ISBN 978-0-85404-122-0 Kanaan, N.; Marti, S.; Moliner, V.; Kohen, A., “QM/MM study of Thymidylate Synthase: Enzymatic motions and the temperature dependence of the rate-limiting step”, J. Phys. Chem. A.* 2009, 113, 2176–2182 (Special Issue on Chemical Dynamics: Max Wolfsberg Festschrift, Sharon Hammes-Schiffer Ed.). Kohen A., Spotlight: “Deep Tunneling Dominates the Biologically Important Hydride Transfer Reaction from NADH to FMN in Morphinone Reductase” J. Am. Chem. Soc. 2008, (invited Spotlight on JACS 2008, 130, 7092, http://pubs.acs.org/JACSbeta/jvi/issue3.html). Yahashiri, A.; Howell, E.E.; Kohen, A., “Tuning of the H-Transfer Coordinate in Primitive vs. Well-Evolved Enzymes”, ChemPhysChem* 2008, 9, 980-982. Bandaria, J.; Dutta, S.; Hill, S.; Kohen, A.; Cheatum, C. Fast Enzyme Dynamics at the Active Site of Formate Dehydrogenase. J. Am. Chem. Soc. 2008, 130, 22-23 (Communication). Hong, B.; Maley, F.; Kohen, A. The Role of Y94 in Proton and Hydride Transfers Catalyzed by Thymidylate Synthase. Biochemistry. 2007, 46, 14188-14197. Chernyshev, A.; Fleischmann,T.; Koehn, E.M.; Lesley, S.A.; Kohen, A. The relationships between oxidase and synthase activities of flavin dependent thymidylate synthase (FDTS). Chem. Commun. 2007, 2861-2863 Kanaan, N.; Marti, S.; Moliner, V.; Kohen, A. A QM/MM Study of the catalytic mechanism of the thymidylate synthase. Biochemistry. 2007, 46, 3704-3713. Chernyshev, A.; Fleischmann, T.; Kohen, A. Enzymes of thymidyl biosynthesis as antibiotic targets Appl. Microbiol. Biotech. 2007, 74, 282-289 (invited review). Kohen, A. Coupled motion and dynamics in enzyme catalysis, in Hydrogen-Transfer Reactions, Hynes, J.T., Klinman, J.P., Limbach, H.H., Schowen, R.L. Eds., Wiley VCH, Weinheim, 2007, Vol. 4, Chapter 12, 1311-1340. [Invited Chapter]. Kohen, A., “Kinetic isotope effects as probes for hydrogen tunneling in enzyme catalysis” in Isotope Effects in Chemistry and Biology, Kohen, A. and Limbach, H.H. Eds., Taylor & Francis -CRC Press, Boca Raton, FL, 2006, Ch. 28, pp-743-764. ISBN 0824724496 [invited chapter] Wang, L.; Goodey, N.M.; Benkovic, S.J.; Kohen, A. Coordinated Effects of Distal Mutations on Environmentally Coupled Tunneling in Dihydrofolate Reductase. Proc. Natl. Acad. Sci. USA* 2006, 103, 15753-15758. Markham, K.A.; Kohen, A. Analytical Procedures for the Preparation, Isolation, Analysis and Preservation of Reduced Nicotinamides. Curr. Anal. Chem., 2006, 2, 379-388 (invited review). Hong, B.; Haddad, M.; Maley, F.; Jensen, J.H.; Kohen, A. Hydride transfer versus hydrogen radical transfer in thymidylate synthase. J. Am. Chem. Soc. (communication) 2006, 128, 5636 - 5637 Mason, A.; Agrawal, N.; Washington, T.; Lesley, S.A.; Kohen, A. A lag-phase in the reduction of flavin dependent thymidylate synthase (FDTS) revealed a mechanistic missing link. Chem. Comm. 2006, 1781 - 1783. Limbach, H.H.; Lopez, J.M.; Kohen, A. Arrhenius curves of hydrogen transfers: Tunnel effects, isotope effects and effects of pre-equilibria. Phil. Trans. R. Soc. B, 2006, 361,1399 - 1415. Wang, L.; Goodey, N.M.; Benkovic, S.J.; Kohen, A. The role of enzyme dynamics and tunneling in catalyzing hydride transfer: studies of distal mutations of dihydrofolate reductase. Phil. Trans. R. Soc. B, 2006, 361, 1307-1215. Wang, L.; Tharp, S.; Seltzer, T.; Benkovic, S.J.; Kohen, A. Effects of a distal mutation on active site chemistry. Biochemistry, 2006, 45, 1383-1392. Pu, J.; Ma, S.; Garcia-Viloca, M.; Gao, J.; Truhlar, D.G.; Kohen, A. Nonperfect synchronization of reaction center rehybridization in the transition state of the hydride transfer catalyzed by dihydrofolate reductase. J. Am. Chem. Soc. 2005, 127, 14789-14886.

Selected Recent Publications- Amnon Kohen