Poster abstracts

Poster number 29 submitted by Ting-fang He

Short-Range Electron Transfer in Proteins

Ting-fang He (OSBP), Chih-Wei Chang (Physics)

Abstract:
Solvent serves to stabilize the molecule (solute) present in solution and, by doing so, can modulate the dynamics of light-induced electron transfer (ET). This modulation is sometimes of appreciable magnitude and has been a subject for decades. In photoinduced ET reaction, light is used to initiate the process by exciting the donor or acceptor but, at the same time, the electronic jump in molecule also creates a significant perturbation to the environment. Solvent in response to the perturbation will undergo a series of relaxations, in an attempt to minimize the entire system energy. Such motion is called solvation. It is by this process that solvent can manipulate the ongoing ET somehow. Interestingly, in biological systems, trapped water and polar/charged sidechains at the active site remain a certain degree of freedom and are still allowed to move within certain limits. Such restricted motions represent the active-site solvation dynamics and can affect the subsequent ET. Many light-dependent functions such as photosynthesis and circadian rhythm are only feasible by the success of initial ET. In this regard, any “dynamic correlation” between ET and the active-site solvation is of great importance. In the present study, we used a biological model system of D. vulgaris flavodoxin to evaluate such correlation.

References:
1.Wang H, Lin S, Allen JP, Williams JC, Blankert S, Laser C, and Woodbury NW (2007) Protein dynamics control the kinetics of initial electron transfer in photosynthesis. Science 316:747-750.

2.Watt W, Tulinsky A, Swenson RP, Watenpaugh KD (1991) Comparison of the crystal structures of a flavodoxin in its three oxidation states at cryogenic temperatures. J Mol Biol 218:195-208.

3.Sumi H and Marcus RA (1986) Dynamical effects in electron transfer reactions. J Chem Phys 84:4894-4814.

Keywords: Flavodoxin, Electron Trnasfer, Ultrafast dynamics