Details

Autor(en) / Beteiligte

• Book, Lewis D
• Arnett, David C
• Hu, Hanbo
• Scherer, Norbert F

Titel

Ultrafast Pump−Probe Studies of Excited-State Charge-Transfer Dynamics in Blue Copper Proteins

Ist Teil von

• The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory, 1998-06, Vol.102 (23), p.4350-4359

Ort / Verlag

American Chemical Society

Erscheinungsjahr

1998

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• We report the results of ultrafast pump−probe measurements on three blue copper proteins:  spinach plastocyanin, poplar plastocyanin, and human ceruloplasmin. Electronic population dynamics and vibrational coherences involving d → d transitions of the blue copper active site are observed using both wavelength-integrated and wavelength-resolved detection. Depending on the protein and the method of detection, the pump-induced bleaches of the electronic ground state decay with time constants of 230−300 fs. The pump−probe signals are modulated by oscillations that correspond to vibrational coherences induced by the ultrashort pulses. The frequencies of some of these oscillations can be matched with modes observed in resonance Raman studies of these proteins. For spinach plastocyanin and ceruloplasmin, wavelength-resolved signals reveal a previously unreported vibration at ∼500 cm-1 whose decay dynamics are consistent with the excited-state lifetime. The origin of this mode is argued to result from Duschinsky rotation. The relevance of these pump−probe results to the development of a model for biological electron transport in these proteins is discussed.