Professor Warren F. Beck
Department of Chemistry
Michigan State University
East Lansing, Michigan 48824 USA
Office: Room 3 Chemistry; 517/355-9715 x213. Fax: 517/353-1793
Email: beck at chemistry.msu.edu
Laboratories: Rooms 4, 6, 16, 40, and 52 Chemistry
Vitae: B.S. 1982, Davidson College; Ph.D., Yale University, 1988 (with Gary Brudvig); Miller Institute Postdoctoral Fellowship, University of California, Berkeley, 1989-91 (with Kenneth Sauer); Assistant Professor, 1991-1998, Vanderbilt University; Associate Professor, Vanderbilt University, 1998; Associate Professor, Michigan State University, 1999-present.
Honors: Phi Beta Kappa (1982); National Science Foundation Graduate Fellowship (1982–1985); Kent Fellowship, Department of Chemistry, Yale University (1982–1986); Richard Wolfgang Dissertation Prize, Department of Chemistry, Yale University (1988); Miller Institute Postdoctoral Fellowship, University of California, Berkeley (1989–1991); Searle Scholarship, Chicago Community Trust/Searle Scholars Program (1992–1995); Lilly Endowment Teaching Fellowship (1993–1994); Cottrell Scholars Award, Research Corporation (1994).
Teaching
CEM 392: Quantum Chemistry, Spring 2008
Research
We employ ultrafast laser spectroscopy and time-resolved fluorescence spectroscopy to study reaction dynamics in condensed phases and in proteins. Current projects focus on the role played by intermolecular vibrational modes in electron-transfer reactions and on the dynamics of proteins displaced far from the equilibrium (or native) structure.
The Beck laboratory acknowledges support from the National Science Foundation's Molecular Biophysics (MCB) and Structure and Reactivity (CHE) programs (MCB-052002).
Intermolecular Vibrational Coherence and Electron Transfer
This project addresses the structural origin and dynamical role of the vibrational modes in the 100-cm-1 regime that are coupled to long-distance electron-transfer reactions in the photosynthetic reaction center and in redox proteins. Our results show that these modes predominantly arise from intermolecular interactions with clustered molecules in the first solvation shell. Not only do the intermolecular modes have a dominant impact on the electron-transfer dynamics by controlling the Marcus reorganization energy and hence the overall activation energy for the reaction, they control the structural reorganization that occurs in response to the formation of net charges in the product states. This is a trapping reorganization that plays an important role in determining the reversibility of the electron-transfer reactions in photosynthesis. In order to detect these interactions selectively in bacteriochlorophyll and porphyrin systems, we use a time-domain version of resonance Raman spectroscopy that is performed with femtosecond pump–probe, dynamic-absorption and transient-grating methods. We plan to extend this project to the dynamics of intramolecular metal-to-ligand and metal-to-metal electron transfer in solution.
Nonequilibrium Protein Dynamics
This project focuses on how proteins evolve structurally when they are displaced from the native structure. We have recently discovered that the radiationless decay of a covalently attached chromophore can be exploited to drive structural transitions from the native fold to a range of partially unfolded or unfolded states. This new approach will allow us to study the dynamics of protein unfolding and refolding from intermediate structures on the protein-folding energy landscape; because we can generate the starting structures optically, rather than by rapid-flow mixing from a chemically denatured state or via a temperature jump, we can study the reaction dynamics with complete control of the solvent composition and temperature. This innovation will permit us to study how protein–solvent interactions play a role in the reaction dynamics. Further, we will be able to obtain true Arrhenius activation-energy parameters for protein folding reactions for the first time. In this work, we use picosecond time-resolved fluorescence spectroscopy to detect the random, diffusive motions that occur in the 100-ps–20-ns regime using the dynamic Stokes shift of an intrinsic chromophore as a probe. We also use femtosecond transient grating and stimulated photon echo spectroscopy to study the fluctuations of a protein that have characteristic time scales in the sub-100-ps regime.
Recent Publications
Shelly, K. R.; Golovich, E. C., Dillman, K. L., and Beck, W. F. "Intermolecular vibrational coherence in the bacteriochlorophyll proteins B777 and B820 from Rhodospirillum rubrum." J. Phys. Chem. B 2008, 112, 1299–1307.
Lampa-Pastirk, S.; Beck, W. F. “Intramolecular vibrational preparation of the unfolding transition state of Zn(II)-substituted cytochrome c.” J. Phys. Chem. B 2006, 110, 22971–22974. Featured as the cover article for the 23 November 2006 issue.
Shelly, K. R.; Golovich, E. C.; Beck, W. F. “Intermolecular vibrational coherence in bacteriochlorophyll a with clustered polar solvent molecules.” J. Phys. Chem. B 2006, 110, 20586–20595.
Lampa-Pastirk, S.; Beck, W. F. “Polar solvation dynamics in Zn(II)-substituted cytochrome c: diffusive sampling of the energy landscape in the hydrophobic core and solvent-contact layer.” J. Phys. Chem. B 2004, 108, 16288–16294.
Lampa-Pastirk, S.; Lafuente, R. C.; Beck, W. F. “Excited-state axial-ligand photodissociation and nonpolar protein-matrix reorganization in Zn(II)-substituted cytochrome c.” J. Phys. Chem. B 2004, 108, 12602–12607.
Carson, E. A.; Diffey, W. M.; Shelly, K. R.; Lampa-Pastirk, S.; Dillman, K. L.; Schleicher, J. M.; Beck, W. F. “Dynamic-absorption spectral contours: vibrational phase-dependent resolution of low-frequency coherent wave-packet motion of IR144 on the ground-state and excited-state π→π* surfaces.” J. Phys. Chem. A 2004, 108, 1489–1500.
Shelly, K. R.; Carson, E. A.; Beck, W. F. “Vibrational coherence from the dipyridine complex of bacteriochlorophyll a: intramolecular modes in the 10–220-cm-1 regime, intermolecular solvent modes, and relevance to photosynthesis.” J. Am. Chem. Soc. 2003, 125, 11810–11811.
Beck, W. F. “Ultrafast Spectroscopy.” In Encyclopedia of Chemical Physics and Physical Chemistry; Moore, J. H., Spencer, N. D., Eds.; Institute of Physics Publishing, Ltd.: Bristol, England, 2001; Volume II, pp 1743–1772.