Transient and persistent hole burning of the reaction center of photosystem II

Abstract

Transient hole burned spectra for the primary donor state, P680*, of the photosystem II (PSII) reaction center (RC) are reported. The RC complex was prepared by a modification of the Nanba and Satoh procedure. The P680* hole profile at 4.2 K consists of a weak but relatively sharp zero-phonon hole (width 5-6 cm{sup {minus}1}) superimposed on a broad hole (width {approx} 130 cm{sup {minus}1}). This structure is successfully analyzed with the theory of Hayes and co-workers for hole burning in the presence of arbitrarily strong linear electron-phonon coupling. The zero-phonon hole width yields a decay time for P680* of 1.9 {plus minus} 0.2 ps at 4.2 K. Persistent spectral hole burning is also reported for the accessory pigments of PSII RC that absorb in the near vicinity of P680. In contrast with the hole spectra of P680*, which are characterized by strong linear electron-photon coupling, the persistent hole spectra are characterized by weak coupling (strong zero-phonon hole and weak phonon sideband hole).