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Irreversible light‐induced formation of P680 + and reduced cytochrome b 559 in the D1‐D2‐Cyt b‐559 complex at low temperature
Author(s) -
Kaminskaya O.P.,
Shuvalov V.A.
Publication year - 1994
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(94)01122-2
Subject(s) - chemistry , cytochrome b , p680 , cytochrome , photochemistry , biochemistry , gene , enzyme , chloroplast , photosystem i , mitochondrial dna
Cytochrome b 559 in D1‐D2‐Cyt b‐559 complexes from spinach can be photoreduced in the presence of DBMIB at a temperature of 18O–240 K upon continuous illumination. The reduction of Cyt b‐559 is accompanied by oxidation of P680. At 240 K recombination of P680 + and reduced Cyt b‐559 is complete in several seconds. At 220 K and below, the state P680 + Cyt b‐559 red can be trapped for a long time. This indicates that the photoreduced heme is incapable of electron transfer to P680 + at 220 K and below. On the other hand, the chemically reduced heme of Cyt b‐559 is oxidized by P680 + at 77 K. These results are consistent with the presence of two kinds of Cyt b‐559 hemes in D1‐D2‐Cyt b‐559 complexes which participate in different ways in the photochemical reactions.