Effect of temperature on the kinetics of electron transfer from the tetraheme cytochrome to the primary donor in Rhodopseudomonas viridis.
The kinetics of electron transfer from the third highest potential heme (c-552, Em = +20 mV) to the primary donor (P-960) have been measured by flash absorption spectroscopy in isolated reaction centers of Rhodopseudomonas viridis between 300 K and 7 K. The data are analyzed on the basis of three exponential components with a very fast phase (t1/2 = 120 ns) dominating at high temperature and a very slow one (t1/2 = 1.2 ms) at low temperature. This multiphasic behavior is interpreted in terms of the existence of three states with a temperature-dependent population and a very limited effect of the temperature on the kinetics for each state.
Ortega
J M
JM
Département de Biologie Cellulaire et Moléculaire, C.E. Saclay, Gif-sur-Yvette, France.
Mathis
P
P
D003080:Cold Temperature; D003574:Cytochrome c Group / Q000378:metabolism*; D004579:Electron Transport; D007700:Kinetics; D010788:Photosynthesis / Q000502:physiology; D045322:Photosynthetic Reaction Center Complex Proteins / Q000378:metabolism*; D012241:Rhodopseudomonas / Q000378:metabolism*; D013053:Spectrophotometry
D003574:Cytochrome c Group; D045322:Photosynthetic Reaction Center Complex Proteins; C083951:cytochrome c553; C022302:cytochrome C-552