15N electron nuclear double resonance of the primary donor cation radical P+.865 in reaction centers of Rhodopseudomonas sphaeroides: additional evidence for the dimer model.
- 1 December 1984
- journal article
- research article
- Published by Proceedings of the National Academy of Sciences in Proceedings of the National Academy of Sciences
- Vol. 81 (24) , 7792-7796
- https://doi.org/10.1073/pnas.81.24.7792
Abstract
Four 15N hyperfine coupling constants, including signs, were measured by electron nuclear double resonance (ENDOR) and electron nuclear nuclear triple resonance (TRIPLE) for the bacteriochlorophyll a radical cation, BChla+, in vitro and for the light-induced primary donor radical cation, .**GRAPHIC**. in reaction centers of R. sphaeroides R-26. A comparison of the data shows that the hyperfine coupling constants have the same sign in both radicals and are .apprx. 2 times smaller in .**GRAPHIC**. These results provide additional evidence that .**GRAPHIC**. is a bacteriochlorophyll dimer and are in contradiction with the monomer structure of .**GRAPHIC**. recently proposed by O''Malley and Babcock. The reduction factors of the individual 15N couplings, together with the evidence from proton ENDOR data and molecular orbital calculations, indicate a dimer structure in which only 2 rings (either I and I or III and III) of the bacteriochlorophyll macrocycles overlap.This publication has 9 references indexed in Scilit:
- Spectral properties of protonated Schiff base porphyrins and chlorins. INDO-CI calculations and resonance Raman studiesJournal of the American Chemical Society, 1984
- Structural studies of the primary donor cation radical P 870 +· in reaction centers of Rhodospirillum rubrum by electron-nuclear double resonance in solutionProceedings of the National Academy of Sciences, 1984
- Electron nuclear double resonance evidence supporting a monomeric nature for P700 + in spinach chloroplastsProceedings of the National Academy of Sciences, 1984
- Photosynthetic Bacterial Reaction Centers: Interactions Among the Bacteriochlorophylls and BacteriopheophytinsAnnual Review of Biophysics and Bioengineering, 1982
- STEREOELECTRONIC PROPERTIES OF PHOTOSYNTHETIC AND RELATED SYSTEMS—VII. AB INITIO QUANTUM MECHANICAL CHARACTERIZATION OF THE ELECTRONIC STRUCTURE AND SPECTRA OF CHLOROPHYLLIDE a AND BACTERIOCHLOROPHYLLIDE a CATION RADICALSPhotochemistry and Photobiology, 1980
- Ligated chlorophyll cation radicals: Their function in photosystem II of plant photosynthesisProceedings of the National Academy of Sciences, 1979
- MODELS FOR ANTENNA AND REACTION CENTER CHLOROPHYLLS*Annals of the New York Academy of Sciences, 1975
- ENDOR EXPERIMENTS ON CHLOROPHYLL AND BACTERIOCHLOROPHYLL IN VITRO AND IN THE PHOTOSYNTHETIC UNIT*Annals of the New York Academy of Sciences, 1975
- Electron Spin Resonance of Chlorophyll and the Origin of Signal I in PhotosynthesisProceedings of the National Academy of Sciences, 1971