Research Interests

The protein environment of enzyme active sites is important in facilitating enzymatic reactions. The protein binds the substrate holding it in a particular geometry so that nearby functional groups are oriented to stabilize the transition state. These functional groups are involved in the reaction mechanism acting as hydrogen-bond partners, providing an electrostatic environment favorable for the reaction, and taking part as acidic or basic groups in proton-transfer reactions. The reaction kinetics are controlled by these local interactions with the protein. This static picture of the protein/substrate interactions, however, is an incomplete description of the catalytic process because fluctuations of these protein functional groups can also be important in the reaction mechanism. In enzymatic hydrogen-transfer reactions, for example, fluctuations of the protein can cause a time-dependent variation in the donor-acceptor separation resulting in large changes in the hydrogen-transfer barrier height. We use 2D IR correlation spectroscopy to study the fluctuations of the enzyme active site and the specific interactions that control the chemistry.

Recent Publications

• Humston, J.J.; Bhattacharya, I.; Jacob, M.; Cheatum, C.M.  Compressively Sampled Two-Dimensional Infrared Spectroscopy That Preserves Line Shape Information. J. Phys. Chem. A 2017, 121, 3088-3093
• Pagano, P.; Guo, Q.; Kohen, A.; Cheatum, C.M.  Oscillatory Enzyme Dynamics Revealed by Two-Dimensional Infrared Spectroscopy. J. Phys. Chem. Lett. 2016, 7, 2507-11
• Guo, Q.; Gakhar, L.; Wickersham, K.; Francis, K.; Vardi-Kilshtain, A.; Major, D. T.; Cheatum, C. M.; Kohen, A.  Structural and Kinetic Studies of Formate Dehydrogenase from Candida boidinii.  Biochemistry 2016, 55, 2760-71
• Guo, Q.; Pagano, P.; Li, Y.L.; Kohen, A.; Cheatum, C.M.  Line Shape Analysis of Two-Dimensional Infrared Spectra. J. Chem. Phys. 2015, 142, 212427 
• Rock, W.; Li, Y.L.; Pagano, P.; Cheatum, C.M.  2D IR Spectroscopy Using Four-Wave Mixing, Pulse Shaping, and IR Upconversion: A Quantitative Comparison.  J. Phys. Chem. A 2013, 117, 6073-6083 
• Cheatum, C.M. and Kohen, A.   Relationship of Femtosecond-Picosecond Dynamics to Enzyme-Catalyzed H-Transfer. Topics in Current Chemistry 2013, 128, 407-446
• Roston, D.; Cheatum, C.M.; Kohen, A.  Hydrogen Donor-Acceptor Fluctuations from Kinetic Isotope Effects: A Phenomenological Model. Biochemistry 2012, 51, 6860-6870
• Dutta, S.; Yun-Liang, L.; Houtman, J.C.D.; Kohen, A.; Cheatum, C.M.  3-Picolyl Azide Adenine Dinucleotide as a Probe of Femtosecond to Picosecond Time Scale Enzyme Dynamics. J. Phys. Chem B 2012, 116, 542-548.
• Dutta, S.; Rock, W.; Cook, R.J.; Kohen, A.; Cheatum, C.M.  2D IR Spectroscopy of Azido-Nicotinamide Adenine Dinucleotide in Water. J. Chem. Phys 2011, 135, 055106-6.
• Nydegger, M.;  Rock, W.; Cheatum, C.M.  2D IR Spectroscopy of the C-D Stretching Vibration of the Deuterated Formic Acid Dimer. Chem. Phys. 2011,13, 6098-6104.
• Bandaria, J.N.; Dutta, S.; Nydegger, M.; Rock, W.; Kohen, A.; Cheatum, C.M.  Characterizing the Dynamics of Functionally Relevant Complexes of Formate Dehydrogenase. Proc. Natl. Acad. Sci. U.S.A. 2010, 107, 17974-17979.
• Dutta, S.; Cook, R.J., Houtman J.C.D.; Kohen, A.; Cheatum, C.M.  Characterization of Azido-NAD⁺ to Assess its Potential as a 2D IR Probe of Enzyme Dynamics. Analytical Biochem. 2010, 407, 241-246.
• Nydegger, M.; Dutta, S.; Cheatum, C.M.  2D IR Study of 3-Azidopyridine as a Potential Spectroscopic Reporter of Protonation State. J. Chem. Phys. 2010,133, 134506