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Modified reaction centers from Rhodobacter sphaeroides R26
Author(s) -
Struck A.,
Scheer H.
Publication year - 1990
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(90)80598-d
Subject(s) - bacteriochlorophyll , rhodobacter sphaeroides , photosynthetic reaction centre , chemistry , monomer , photochemistry , pigment , stereochemistry , residue (chemistry) , photosynthesis , organic chemistry , biochemistry , electron transfer , polymer
Incubation of photosynthetic reaction centers from Rhodobacter sphaeroides R26 with exogenous 13 2 ‐OH‐bacteriochlorophyll a p or a GG according to Scheer et al. (1987) results in the exchange of endogenous bacteriochlorophyll a p . The exchange amounts to ⩽ 50% according to HPLC analysis, corresponding to a complete replacement of the ‘monomeric’ bacteriochlorophylls, b m and b l , by exogenous pigment. The absorption spectra show small, but distinct changes in the Q x ‐region of the bacteriochlorophylls, and bleaching of the modified reaction centers is retained. The corresponding binding sites must be accessible from the exterior, and allow for the introduction of a polar residue at C‐13 2 . This is supported by the observation of side reactions of the endogenous ‘monomeric’ bacteriochlorophylls within the reaction center pigments, e.g. epimerization and hydroxylation at C‐13 2 .