help button home button Biophys. J.
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS

Biophysical Journal 61: 1462-1469 (1992)
© 1992 the Biophysical Society

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Zurdo, J
Right arrow Articles by Ramírez, J M
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Zurdo, J
Right arrow Articles by Ramírez, J M

Enhancement of carotenoid-to-chlorophyll singlet energy transfer by carotenoid-carotenoid interaction.

J Zurdo, C Fernández-Cabrera and J M Ramírez

Centro de Investigaciones Biológicas, C.S.I.C., Madrid, Spain.

ABSTRACT

The apparent quantum yield of singlet-singlet spirilloxanthin-to-bacteriochlorophyll a energy transfer increases linearly with the residual spirilloxanthin content in Rhodospirillum rubrum membrane vesicles from which this carotenoid has been partially removed. Since it has been previously shown that carotenoid-carotenoid interaction is a linear function of the residual spirilloxanthin level in the major pigment-protein complex of those vesicles (Zurdo, J., R. M. Lozano, C. Fernandez-Cabrera, and J. M. Ramirez. 1991. Biochem. J. 274:881-884), it appears that such degenerate interaction enhances singlet energy transfer. Part of the enhancement may be explained if the energy donor is the spirilloxanthin 1Bu----1Ag (S2----S0) transition, because exciton coupling probably brings its energy closer to that of the Qx (S2----S0) transition of bacteriochlorophyll. In contrast, it seems that the possible stabilization of the spirilloxanthin 2Ag (S1) state would hardly improve energy transfer, because this hidden state probably lies below the S1 bacteriochlorophyll state. In any case, the stabilizing effects of carotenoid-carotenoid interactions seem insufficient to explain the enhancement of energy transfer. Direct or indirect effects of carotenoid dimerization on the three-dimensional structure of the pigment cluster appear to be required to account for such enhancement.






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 1992 by the Biophysical Society.