A NATIVE ELECTROSTATIC ENVIRONMENT NEAR Q(B) IS NOT SUFFICIENT TO ENSURE RAPID PROTON DELIVERY IN PHOTOSYNTHETIC REACTION CENTERS

Citation
M. Valeriolepiniec et al., A NATIVE ELECTROSTATIC ENVIRONMENT NEAR Q(B) IS NOT SUFFICIENT TO ENSURE RAPID PROTON DELIVERY IN PHOTOSYNTHETIC REACTION CENTERS, FEBS letters, 407(2), 1997, pp. 159-163
Citations number
31
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Biophysics,Biology
Journal title
ISSN journal
0014-5793
Volume
407
Issue
2
Year of publication
1997
Pages
159 - 163
Database
ISI
SICI code
0014-5793(1997)407:2<159:ANEENQ>2.0.ZU;2-T
Abstract
Flash-induced absorption spectroscopy has been used to characterize Rh odobacter capsulatus reaction centers mutated in the secondary quinone acceptor site (Q(B)). We compared the wild-type, the L212Glu-L2l3Asp --> Ala-Ala photosynthetically incompetent double mutant (DM), and two photocompetent revertants, the DM+L217Arg --> Cys and the DM+M5Asn -- > Asp strains, The electrostatic environment for O-B(-) is different i n the two revertant strains, Only the L217Arg --> Cys mutation nearly restores the native electrostatic environment of Q(B)(-). However, the level of recovery of the reaction center function, measured by the ra tes of second electron transfer and cytochrome c turnover, is quite in complete in both strains, This shows that a wild-type-like electrostat ic environment of Q(B)(-) cannot ensure on its own, rapid and efficien t proton transfer to Q(B)(-). (C) 1997 Federation of European Biochemi cal Societies.