title: Spectral hole burning of the primary electron donor state of Photosystem I.
abstract: Persistent photochemical hole burned profiles are reported for the primary electron donor state P700 of the reaction center of PS I. The hole profiles at 1.6 K for a wide range of burn wavelengths (λB) are broad (FWHM∼310 cm(-1)) and for the 45:1 enriched particles studied exhibit no sharp zero-phonon hole feature coincident with λB. The λB hole profiles are analyzed using the theory of Hayes et al. [J Phys Chem 1986, 90: 4928] for hole burning in the presence of arbitrarily strong linear electron-phonon coupling. A Huang-Rhys factor S in the range 4-6 and a corresponding mean phonon frequency in the range 35-50 cm(-1) together with an inhomogeneous line broadening of∼100 cm(-1) are found to provide good agreement with experiment. The zero-point level of P700(*) is predicted to lie at∼710 nm at 1.6K with an absorption maximum at∼702 nm. The hole spectra are discussed in the context of the hole spectra for the primary electron donor states of PS II and purple bacteria.
authors.affiliation: Ames Laboratory-USDOE, Iowa State University, 50011, Ames, Iowa, U.S.A..
authors.forename: J K
authors.initials: JK
authors.lastname: Gillie
authors.forename: P A
authors.initials: PA
authors.lastname: Lyle
authors.forename: G J
authors.initials: GJ
authors.lastname: Small
authors.forename: J H
authors.initials: JH
authors.lastname: Golbeck