Mixed exciton-charge-transfer states in photosystem II: Stark spectroscopy on site-directed mutants.

ABSTRACT: We investigated the electronic structure of the photosystem II reaction center (PSII RC) in relation to the light-induced charge separation process using Stark spectroscopy on a series of site-directed PSII RC mutants from the cyanobacterium Synechocystis sp. PCC 6803. The site-directed mutations modify the protein environment of the cofactors involved in charge separation (P(D1), P(D2), Chl(D1), and Phe(D1)). The results demonstrate that at least two different exciton states are mixed with charge-transfer (CT) states, yielding exciton states with CT character: (P(D2)(δ)(+)P(D1)(δ)(-)Chl(D1)) (673 nm) and (Chl(D1)(δ)(+)Phe(D1)(δ)(-)) (681 nm) (where the subscript indicates the wavelength of the electronic transition). Moreover, the CT state P(D2)(+)P(D1)(-) acquires excited-state character

SUBMITTER: Romero E 

PROVIDER: S-EPMC3400784 | biostudies-literature | 2012 Jul

REPOSITORIES: biostudies-literature