10.1021/bi970024r.s001
Nerine J. Cherepy
Nerine J.
Cherepy
Andrew P. Shreve
Andrew P.
Shreve
Laura J. Moore
Laura
J. Moore
Steven G. Boxer
Steven G.
Boxer
Richard A. Mathies
Richard A.
Mathies
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>
American Chemical Society
1997
278 K
photosynthetic reaction center
RC
Raman spectra
resonance Raman spectra
multimode vibronic models
P vibrational spectrum
section
Primary Electron Donor
95 K
Q y Resonance Raman Spectra
H spectra exhibit
1997-07-15 00:00:00
Journal contribution
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
Q<sub>y</sub>-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 <i>Rhodobacter sphaeroides</i> 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 <i>in vitro</i>. 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.