Document Detail


Femtosecond spectral evolution of the excited state of bacterial reaction centers at 10 K.
MedLine Citation:
PMID:  1731331     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The femtosecond spectral evolution of reaction centers of Rhodobacter sphaeroides R-26 was studied at 10 K. Transient spectra in the near infrared region, obtained with 45-fs pulses (pump pulses centered at 870 nm and continuum probe pulses), were analyzed with associated kinetics at specific wavelengths. The t = 0-fs transient spectrum is very rich in structure; it contains separate induced bands at 807 and 796 nm and a bleaching near 760 nm, reflecting strong changes in interaction between all pigments upon formation of the excited state. A complex spectral evolution in the 800-nm region, most notably the bleaching of the 796-nm band, takes place within a few hundred femtosecond--i.e., on a time scale much faster than electron transfer from the primary donor P to the bacteriopheophytin acceptor HL. The remarkable initial spectral features and their evolution are presumably related to the presence of HL, as they were not observed in the DLL mutant of Rhodobacter capsulatus, which lacks this pigment. A simple linear reaction scheme with an intermediate state cannot account for our data; the initial spectral evolution must reflect relaxation processes within the excited state. The importance for primary photochemistry of long distance interactions in the reaction center is discussed.
Authors:
M H Vos; J C Lambry; S J Robles; D C Youvan; J Breton; J L Martin
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Proceedings of the National Academy of Sciences of the United States of America     Volume:  89     ISSN:  0027-8424     ISO Abbreviation:  Proc. Natl. Acad. Sci. U.S.A.     Publication Date:  1992 Jan 
Date Detail:
Created Date:  1992-02-18     Completed Date:  1992-02-18     Revised Date:  2010-09-10    
Medline Journal Info:
Nlm Unique ID:  7505876     Medline TA:  Proc Natl Acad Sci U S A     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  613-7     Citation Subset:  IM    
Affiliation:
Laboratoire d'Optique Appliquée, Institut National de la Santé et de la Recherche Médicale Unité 275, Ecole Polytechnique-Ecole Nationale Supérieure de Techniques Avancées, Palaiseau, France.
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MeSH Terms
Descriptor/Qualifier:
Cold Temperature
Kinetics
Photochemistry
Photosynthesis
Photosynthetic Reaction Center Complex Proteins / metabolism*
Rhodobacter capsulatus
Rhodobacter sphaeroides
Spectrum Analysis
Grant Support
ID/Acronym/Agency:
R1GM42645A/GM/NIGMS NIH HHS
Chemical
Reg. No./Substance:
0/Photosynthetic Reaction Center Complex Proteins
Comments/Corrections

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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