General Colloquium:

January 17 - 4:00pm Phys 223
(Coffee at 3:30p.m. in room 242)

Sergei Savikhin

Physics Department, Purdue University

Photosystem I: following the path of energy transfer

Photosystem I (PS I) is a major photosynthetic pigment-protein complex which initiates photosynthesis in all green plants and various bacteria. It contains ~100 chlorophyll molecules. Most of them form light-harvesting antenna, which absorbs light and passes excitation energy to the reaction center (RC) consisting of few chlorophylls. Once excitation reaches RC it initiates charge separation and transfers electron out from RC via series of intermediate molecules to one side of a cell membrane. The energy of this electron is later used by the cell to drive vital processes. In this talk I will present the results of our optical time resolved experiments which reveal the dynamics and pathways of energy and electron transfer processes in PS I in real time. Based on recent X-ray structure of PS I, a detailed model of energy transfer was built and used to simulate experimental results. In addition to native (wild) type PS I complexes, a series of mutants were engineered and studied to provide further details of the structure-function relationship in this important protein.

Website

http://www.physics.purdue.edu/~sergei/