[Temperature dependence of protein globule polarization and electron transport in preparations of photosynthetic reaction centers from Rhodopseudomonas sphaeroides].
Differential "light-minus-dark" spectra were obtained for reaction center (RC) preparations cooled in the light and in the dark at 77 K. The two types of preparations were found to display different spectral features in the spectral regions 760-770, 790-810, 880-990 nm. Differences in the spectra of the two types were found to exist in preparations cooled to temperatures below 120-100 K, whereas at temperatures above 130 K such differences were not observed. The observed spectral changes may be associated with the polarization processes occurring in the RC globule. Samples cooled in the light and in the dark show different temperature dependencies of the efficiency of electron transfer to the secondary quinone acceptor. The differences are irreversible after cooling to temperatures below 170 K, and reversible after cooling to 180-200 K. It is postulated that the observed kinetic changes are reflections of changes in the configuration of the acceptor complex of the RC. The possible existence of a correlation between the polarization processes in the protein globule and the structural configurations of the RC is discussed.
D001426:Bacterial Proteins / Q000378:metabolism*; D001429:Bacteriochlorophylls / Q000378:metabolism; D003080:Cold Temperature; D004579:Electron Transport; D008027:Light; D045342:Light-Harvesting Protein Complexes; D010084:Oxidation-Reduction; D045322:Photosynthetic Reaction Center Complex Proteins; D011487:Protein Conformation; D012242:Rhodobacter sphaeroides / Q000378:metabolism*; D013053:Spectrophotometry
D001426:Bacterial Proteins; D001429:Bacteriochlorophylls; D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins
Temperaturnaia zavisimost' poliarizatsii belkovoĭ globuly i perenosa élektrona v preparatakh fotosinteticheskikh reaktsionnykh tsentrov iz Rhodopseudomonas sphaeroides.