title: Excited state charge-transfer dynamics study of poplar plastocyanin by ultrafast pump-probe spectroscopy and molecular dynamics simulation.
abstract: We have applied ultrafast pump-probe spectroscopy to investigate the excited state dynamics of the blue copper protein poplar plastocyanin, by exciting in the blue side of its 600-nm absorption band. The decay of the charge-transfer excited state occurs exponentially with a time constant of approximately 280 fs and is modulated by well visible oscillations. The Fourier transform of the oscillatory component, besides providing most of the vibrational modes found by conventional resonance Raman, presents additional bands in the low frequency region modes, which are reminiscent of collective motions of biological relevance. Notably, a high frequency mode at approximately 508 cm(-1), whose dynamics are consistent with that of the excited state and already observed for other blue copper proteins, is shown to be present also in poplar plastocyanin. This vibrational mode is reproduced by a molecular dynamics simulation involving the excited state of the copper site.
authors.affiliation: Biophysics & Nanoscience Group, INFM, Dipartimento di Scienze Ambientali, Università della Tuscia, I-01100.Viterbo, Italy
authors.forename: Tiziana
authors.initials: T
authors.lastname: Cimei
authors.forename: Anna
authors.initials: A
authors.lastname: Rita Bizzarri
authors.forename: Giulio
authors.initials: G
authors.lastname: Cerullo
authors.forename: Sandro
authors.initials: S
authors.lastname: De Silvestri
authors.forename: Salvatore
authors.initials: S
authors.lastname: Cannistraro
mesh_terms: D003198:Computer Simulation; D003300:Copper / Q000378:metabolism; D003545:Cysteine / Q000737:chemistry / Q000378:metabolism; D005583:Fourier Analysis; D008958:Models, Molecular; D008968:Molecular Conformation; D010970:Plastocyanin / Q000737:chemistry*; D032107:Populus / Q000737:chemistry*; D013053:Spectrophotometry / Q000295:instrumentation* / Q000379:methods*; D013455:Sulfur / Q000378:metabolism; D013997:Time Factors
chemical_list: D013455:Sulfur; D003300:Copper; D010970:Plastocyanin; D003545:Cysteine