Excitation energy transfer in the photosystem I

Webber, Andrew N

关键词: Photosystem I;    P700;    electron transfer;    excitation energy transfer;   

DOI  :  10.2172/1051681
RP-ID  :  DOE/ER20349-F
PID  :  OSTI ID: 1051681
Others  :  Other: LMS0146

学科分类：再生能源与代替技术

美国|英语

来源: SciTech Connect

【 摘 要 】

Photosystem I is a multimeric pigment protein complex in plants, green alage and cyanobacteria that functions in series with Photosystem II to use light energy to oxidize water and reduce carbon dioxide. The Photosystem I core complex contains 96 chlorophyll a molecules and 22 carotenoids that are involved in light harvesting and electron transfer. In eucaryotes, PSI also has a peripheral light harvesting complex I (LHCI). The role of specific chlorophylls in excitation and electron transfer are still unresolved. In particular, the role of so-called bridging chlorophylls, located between the bulk antenna and the core electron transfer chain, in the transfer of excitation energy to the reaction center are unknown. During the past funding period, site directed mutagenesis has been used to create mutants that effect the physical properties of these key chlorophylls, and to explore how this alters the function of the photosystem. Studying these mutants using ultrafast absorption spectroscopy has led to a better understanding of the process by which excitation energy is transferred from the antenna chlorophylls to the electron transfer chain chlorophylls, and what the role of connecting chlorophylls and A_0 chlorophylls is in this process. We have also used these mutants to investigate whch of the central group of six chlorophylls are involved in the primary steps of charge separation and electron transfer.