TY - JOUR
T1 - An LD-ADMR study on reaction centers of the LH(L131) and LH(M160) hydrogen-bonding mutants of Rhodobacter sphaeroides
AU - Vrieze, J.
AU - Williams, Joann
AU - Allen, James
AU - Hoff, A. J.
N1 - Funding Information:
We thank Saskia Jansen and Susana Shochat for isolating the chromatophores and the reaction centers. This work was supported by the Foundation for Chemical Research (SON) financed by the Netherlands Organization for Sci-enctific Research (NWO).
PY - 1996/9/30
Y1 - 1996/9/30
N2 - Reaction centers of the LH(L131) and LH(M160) mutants of Rhodobacter sphaeroides, which have a leucine near the primary donor, a bacteriochlorophyll dimer, changed into a histidine, have been investigated with linear-dichroic absorbance-detected magnetic resonance, and the results are compared with those obtained for native reaction centers. The microwave-induced triplet-minus-singlet absorbance-difference spectra of the three reaction centers upon triplet formation of the primary donor show small differences in band shifts in the Q(Y)-region of the accessory bacteriochrorophylls. The orientations of the Q(Y)-transition moments with respect to the dipolar axes of the triplet state of the primary donor were found to be equal for all reaction centers, indicating that the orientation of the triplet axes with respect to the reaction center coordinate frame is the same for all three reaction centers. From this we conclude that the electronic composition of the triplet state and the Q(Y) transitions are basically the same for the mutant and native reaction centers.
AB - Reaction centers of the LH(L131) and LH(M160) mutants of Rhodobacter sphaeroides, which have a leucine near the primary donor, a bacteriochlorophyll dimer, changed into a histidine, have been investigated with linear-dichroic absorbance-detected magnetic resonance, and the results are compared with those obtained for native reaction centers. The microwave-induced triplet-minus-singlet absorbance-difference spectra of the three reaction centers upon triplet formation of the primary donor show small differences in band shifts in the Q(Y)-region of the accessory bacteriochrorophylls. The orientations of the Q(Y)-transition moments with respect to the dipolar axes of the triplet state of the primary donor were found to be equal for all reaction centers, indicating that the orientation of the triplet axes with respect to the reaction center coordinate frame is the same for all three reaction centers. From this we conclude that the electronic composition of the triplet state and the Q(Y) transitions are basically the same for the mutant and native reaction centers.
KW - Absorbance-detected magnetic resonance
KW - Bacterial reaction center
KW - Mutant
KW - Photosynthesis
KW - Triplet state
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U2 - 10.1016/0005-2728(96)00083-7
DO - 10.1016/0005-2728(96)00083-7
M3 - Article
AN - SCOPUS:0030607112
SN - 0005-2728
VL - 1276
SP - 221
EP - 228
JO - Biochimica et Biophysica Acta - Bioenergetics
JF - Biochimica et Biophysica Acta - Bioenergetics
IS - 3
ER -