In this reporting period, papers dealing with the following projects appeared in print or are in press: (1)The kinetics of reversible diffusion influenced reactions (2) Asymptotic relaxation of reversible bimolecular chemical reactions (3) The concentration dependance of the diffusion controlled steady state rate constant (4)The effects of chain stiffness on the dynamics of loop formation in polypeptides and (5) the statistics of transitions in single molecule kinetics. The first three papers deal with various aspects of the role of diffusion in chemical reaction dynamics. The first paper is the culmination of a project started over ten years ago. For all practical purposes it solves the problem of calculating the time course of reversible diffusion influenced reations with arbitrary stoichiometry. In the coming years we hope to collaborate with experimetallist to analyze their kinetic data using our theory. The fourth paper is a collaboration with the Eaton-Hofrichter group on the kinetics of contact formation in polypeptides. This is an elementary step in protein folding and consequently of great current interest. My contibution was to develop the theoretical framework that was used to analyse their experiments.The final paper deals with the theory required to interpret fluorescence resonance energy transfer experiments on protein folding. In these experiments the number of photons emitted by a donor and an acceptor are monitoried. These contain structural information because the efficiency of energy transfer between tne donor and acceptor depend on the distance between them. Given an arbitrary kinetic scheme we showed how to calculate the probability distribution of number of photons emitted during a fixed time window. This work should prove useful in exracting the underlying kinetic mechanism from experiments.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Intramural Research (Z01)
Project #
1Z01DK029019-22
Application #
6673404
Study Section
(LCP)
Project Start
Project End
Budget Start
Budget End
Support Year
22
Fiscal Year
2002
Total Cost
Indirect Cost
Name
U.S. National Inst Diabetes/Digst/Kidney
Department
Type
DUNS #
City
State
Country
United States
Zip Code
Berezhkovskii, Alexander; Hummer, Gerhard; Szabo, Attila (2009) Reactive flux and folding pathways in network models of coarse-grained protein dynamics. J Chem Phys 130:205102
Gopich, Irina V; Nettels, Daniel; Schuler, Benjamin et al. (2009) Protein dynamics from single-molecule fluorescence intensity correlation functions. J Chem Phys 131:095102
Bezrukov, Sergey M; Berezhkovskii, Alexander M; Szabo, Attila (2007) Diffusion model of solute dynamics in a membrane channel: mapping onto the two-site model and optimizing the flux. J Chem Phys 127:115101
Dudko, Olga K; Mathe, Jerome; Szabo, Attila et al. (2007) Extracting kinetics from single-molecule force spectroscopy: nanopore unzipping of DNA hairpins. Biophys J 92:4188-95
Berezhkovskii, Alexander; Szabo, Attila (2006) Perturbation theory of Phi-value analysis of two-state protein folding: relation between p fold and Phi values. J Chem Phys 125:104902
Dudko, Olga K; Hummer, Gerhard; Szabo, Attila (2006) Intrinsic rates and activation free energies from single-molecule pulling experiments. Phys Rev Lett 96:108101
Gopich, Irina; Szabo, Attila (2005) Fluorophore-quencher distance correlation functions from single-molecule photon arrival trajectories. J Phys Chem B 109:6845-8
Berezhkovskii, Alexander; Szabo, Attila (2005) One-dimensional reaction coordinates for diffusive activated rate processes in many dimensions. J Chem Phys 122:14503
Gopich, Irina V; Szabo, Attila (2005) Photon counting histograms for diffusing fluorophores. J Phys Chem B 109:17683-8
Gopich, Irina; Szabo, Attila (2005) Theory of photon statistics in single-molecule Forster resonance energy transfer. J Chem Phys 122:14707

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