TY - JOUR
T1 - Interaction of photosynthetic pigments with various organic solvents. Magnetic circular dichroism approach and application to chlorosomes
AU - Umetsu, Mitsuo
AU - Wang, Zheng Yu
AU - Kobayashi, Masayuki
AU - Nozawa, Tsunenori
N1 - Funding Information:
We are grateful to Prof. Mamoru Mimuro, Dr. Toru Oba and Yukio Imamura for discussion about Chl a and chlorosomes. This work was supported by Grants-in-Aid from the Ministry of Education, Science and Culture, Japan (Nos. 06555257, 07455437, 07750872, 08455377).
PY - 1999/1/27
Y1 - 1999/1/27
N2 - Magnetic circular dichroism (MCD) and absorption spectra have been measured on three intact photosynthetic pigments with the chlorin ring as macrocycle: chlorophyll a, bacteriochlorophyll c and d, in various hydrophilic organic solvents. The MCD intensity of a Q(y)(0-0) transition for the Mg chlorin derivative was sensitive to the coordination state of the central Mg atom by the solvent molecules. The coordination number has been characterized in terms of the relationship between the ratio of Q(y)(0-0) MCD intensity to its dipole strength (B/D) and the difference in energies of Q(x)(0-0) and Q(y)(0-0) transitions. This relationship depends not only on the coordination number of the magnesium (Mg) atom but also on the coordination interaction of the solvent molecules to the Mg atom, and can clarify the spectroscopic change of chlorosomes by alcohol treatment. We propose that the correlation between the MCD intensity of Q(y)(0-0) transition and the energy difference can be used as a new measure for determining the coordination number of the Mg atom and for estimating the interaction strength of the Mg atom with solvent molecules. Copyright (C) 1999 Elsevier Science B.V.
AB - Magnetic circular dichroism (MCD) and absorption spectra have been measured on three intact photosynthetic pigments with the chlorin ring as macrocycle: chlorophyll a, bacteriochlorophyll c and d, in various hydrophilic organic solvents. The MCD intensity of a Q(y)(0-0) transition for the Mg chlorin derivative was sensitive to the coordination state of the central Mg atom by the solvent molecules. The coordination number has been characterized in terms of the relationship between the ratio of Q(y)(0-0) MCD intensity to its dipole strength (B/D) and the difference in energies of Q(x)(0-0) and Q(y)(0-0) transitions. This relationship depends not only on the coordination number of the magnesium (Mg) atom but also on the coordination interaction of the solvent molecules to the Mg atom, and can clarify the spectroscopic change of chlorosomes by alcohol treatment. We propose that the correlation between the MCD intensity of Q(y)(0-0) transition and the energy difference can be used as a new measure for determining the coordination number of the Mg atom and for estimating the interaction strength of the Mg atom with solvent molecules. Copyright (C) 1999 Elsevier Science B.V.
KW - Alcohol treatment
KW - Bacteriochlorophyll c
KW - Chlorosome
KW - Coordination state
KW - Magnetic circular dichroism
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U2 - 10.1016/S0005-2728(98)00170-4
DO - 10.1016/S0005-2728(98)00170-4
M3 - Article
AN - SCOPUS:0032973113
VL - 1410
SP - 19
EP - 31
JO - Biochimica et Biophysica Acta - Bioenergetics
JF - Biochimica et Biophysica Acta - Bioenergetics
SN - 0005-2728
IS - 1
ER -