English   español  
Please use this identifier to cite or link to this item: http://hdl.handle.net/10261/61378
logo share SHARE   Add this article to your Mendeley library MendeleyBASE
Visualizar otros formatos: MARC | Dublin Core | RDF | ORE | MODS | METS | DIDL
Exportar a otros formatos:

Supramolecular arrangement of Rhodospirillum rubrum B880 holochrome as studied by radiation inactivation and electron paramagnetic resonance

AuthorsGingras, Gabriel; Picorel Castaño, Rafael
Issue DateMay-1990
PublisherNational Academy of Sciences (U.S.)
CitationProceedings of the National Academy of Sciences 87 (9): 3405-3409 (1990)
AbstractOxidation of the B880 antenna holochrome gives rise to a 3.8-G linewidth electron paramagnetic resonance (EPR) signal that is considerably narrower than the 13-G signal of monomeric bacteriochlorophyll (Bchl) cation. Radiation inactivation was used to verify a model according to which this linewidth narrowing is due to delocalization over several Bchl molecules. Chromatophores of the photoreaction centerless mutant F24 of Rhodospirillum rubrum were subjected to different doses of gamma-radiation. This induced not only a decay of the EPR signal amplitude but also its linewidth broadening. According to target theory, the induced amplitude decay of the EPR signal had a target size of 10.5 kDa. This is attributed to an elementary structure (alpha1beta1Bchl2), whose number in the membrane would limit the rate of encounter with ferricyanide and thus the formation of unpaired spins. We applied Bernoulli statistics to predict, for a given survival probability of the signal, the number of surviving elementary structures in aggregates of (alpha1beta1Bchl2)n where n was varied from 4 to 7. Using an equation that predicted the Bchl special pair in the photo-reaction center, we were able to simulate the observed relationship between the EPR linewidth and the dose of radiation. The best fit was obtained with a hexameric structure alpha1beta1Bchl2)6.
Description5 Pags., 5 Figs.
Publisher version (URL)http://www.pnas.org/content/87/9/3405.full.pdf+html
Appears in Collections:(EEAD) Artículos
Files in This Item:
File Description SizeFormat 
PicorelR_linkPNAS_1990.pdf47,04 kBAdobe PDFThumbnail
Show full item record
Review this work

WARNING: Items in Digital.CSIC are protected by copyright, with all rights reserved, unless otherwise indicated.