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Probing native‐like orientation of pigments in modified reaction centers from Rhodobacter sphaeroides R26 by linear dichroism
Author(s) -
Meyer Michaela,
Scheer Hugo,
Breton Jacques
Publication year - 1996
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(96)00869-1
Subject(s) - rhodobacter sphaeroides , bacteriochlorophyll , photosynthetic reaction centre , linear dichroism , chemistry , electron transfer , circular dichroism , photochemistry , redox , pigment , crystallography , photosynthesis , organic chemistry , biochemistry
Site‐specific pigment modifications are useful to investigate structure‐function relationships in photosynthesis. In reaction centers bearing modified (bacterio)pheophytins, changed electron transfer kinetics have been related to the changed redox potentials of the pigments introduced (Huber, H. et al. (1995) Chemical Physics, Special Issue, vol 197 (Hochstrasser, R.M. and Hofacker, G.L. eds.) pp. 297–305; [1]). In order to analyze potentially interfering structural changes induced in these reaction centers by the exchange procedure, in particular mispositioning or misorientation of the pigments, low‐temperature linear dichroism spectra have been measured for reaction centers from Rhodobacter sphaeroides containing modified bacteriopheophytins and bacteriochlorophylls at the sites H AB and B A,B , respectively. They show that all modified pigments are oriented similar to the native ones, and that they do not affect significantly the linear dichroism of the monomeric bacteriochlorophylls and bacteriopheophytins or of the primary donor.