%0 Journal Article
%A Cherepy, Nerine J.
%A Shreve, Andrew P.
%A J. Moore, Laura
%A Boxer, Steven G.
%A Mathies, Richard A.
%D 1997
%T Temperature Dependence of the Qy Resonance Raman Spectra of
Bacteriochlorophylls, the Primary Electron Donor, and Bacteriopheophytins in the
Bacterial Photosynthetic Reaction Center†
%U https://acs.figshare.com/articles/journal_contribution/Temperature_Dependence_of_the_Q_sub_y_sub_Resonance_Raman_Spectra_of_Bacteriochlorophylls_the_Primary_Electron_Donor_and_Bacteriopheophytins_in_the_Bacterial_Photosynthetic_Reaction_Center_sup_sup_/3587814
%R 10.1021/bi970024r.s001
%2 https://acs.figshare.com/ndownloader/files/5673750
%K 278 K
%K photosynthetic reaction center
%K RC
%K Raman spectra
%K resonance Raman spectra
%K multimode vibronic models
%K P vibrational spectrum
%K section
%K Primary Electron Donor
%K 95 K
%K Q y Resonance Raman Spectra
%K H spectra exhibit
%X Qy-excited resonance Raman spectra of the accessory
bacteriochlorophylls (B), the bacteriopheophytins (H), and the primary electron donor (P) in the bacterial
photosynthetic reaction center
(RC) of Rhodobacter sphaeroides have been obtained at 95 and
278 K. Frequency and intensity differences
are observed in the low-frequency region of the P vibrational spectrum
when the sample is cooled from
278 to 95 K. The B and H spectra exhibit minimal changes of
frequencies and relative intensities as a
function of temperature. The mode patterns in the Raman spectra of
B and H differ very little from
Raman spectra of the chromophores in vitro. The Raman
scattering cross sections of B and H are 6−7
times larger than those for analogous modes of P at 278 K. The
cross sections of B and of H are 3−4
times larger at 95 K than at 278 K, while the cross sections of P are
approximately constant with
temperature. The temperature dependence of the Raman cross
sections for B and H suggests that pure
dephasing arising from coupling to low-frequency solvent/protein modes
is important in the damping of
their excited states. The weak Raman cross sections of the special
pair suggest that the excited state of
P is damped by very rapid (<30 fs) electronic relaxation processes.
These resonance Raman spectra
provide information for developing multimode vibronic models of the
excited-state structure and dynamics
of the chromophores in the RC.
%I ACS Publications