Maurice D. Edington

RADIATIONLESS DECAY FROM THE LIGAND-TO-METAL CHARGE-TRANSFER STATE IN THE BLUE COPPER PROTEIN PLASTOCYANIN

Abstract The cysteine S(p π ) → Cu 2+ d x 2 − y 2 ligand-to-metal charge-transfer (LMCT) state in plastocyanin exhibits a time-resolved pump-probe spectrum that has excited-state absorption and stimulated-emission components to the blue and red, respectively, of the absorption maximum. The LMCT state returns to the ground state by populating the d xz + yz → d x 2 − y 2 ligand-field (LF) state. The lack of hole-burned features in the time-resolved spectra implies the presence of intramolecular vibrational redistribution and/or protein-matrix solvation dynamics on a time scale that is shorter than the 125 fs lifetime of the LMCT state.

Inertial Protein-Matrix Solvation of a Light-Harvesting Chromophore

We have employed transient hole-burning spectroscopy (THB) to characterize ultrafast protein-matrix solvation processes in the α subunit of the cyanobacterial light-harvesting protein C-phycocyanin.