+ Site Statistics
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

Electron transfer in reaction centers of Rhodobacter sphaeroides and Rhodobacter capsulatus monitored by fluorescence of the bacteriochlorophyll dimer



Electron transfer in reaction centers of Rhodobacter sphaeroides and Rhodobacter capsulatus monitored by fluorescence of the bacteriochlorophyll dimer



Photosynthesis Research 47(1): 41-49



Spectral and kinetic characteristics of fluorescence from isolated reaction centers of photosynthetic purple bacteria Rhodobacter sphaeroides and Rhodobacter capsulatus were measured at room temperature under rectangular shape of excitation at 810 nm. The kinetics of fluorescence at 915 nm reflected redox changes due to light and dark reactions in the donor and acceptor quinone complex of the reaction center as identified by absorption changes at 865 nm (bacteriochlorophyll dimer) and 450 nm (quinones) measured simultaneously with the fluorescence. Based on redox titration and gradual bleaching of the dimer, the yield of fluorescence from reaction centers could be separated into a time-dependent (originating from the dimer) and a constant part (coming from contaminating pigment (detached bacteriochlorin)). The origin was also confirmed by the corresponding excitation spectra of the 915 nm fluorescence. The ratio of yields of constant fluorescence over variable fluorescence was much smaller in Rhodobacter sphaeroides (0.15±0.1) than in Rhodobacter capsulatus (1.2±0.3). It was shown that the changes in fluorescence yield reflected the disappearance of the dimer and the quenching by the oxidized primary quinone. The redox changes of the secondary quinone did not have any influence on the yield but excess quinone in the solution quenched the (constant part of) fluorescence. The relative yields of fluorescence in different redox states of the reaction center were tabulated. The fluorescence of the dimer can be used as an effective tool in studies of redox reactions in reaction centers, an alternative to the measurements of absorption kinetics.

Please choose payment method:






(PDF emailed within 0-6 h: $19.90)

Accession: 008594083

Download citation: RISBibTeXText

PMID: 24301706

DOI: 10.1007/bf00017752


Related references

Effect of D2O and cryosolvents on the redox properties of bacteriochlorophyll dimer and electron transfer processes in Rhodobacter sphaeroides reaction centers. Bioelectrochemistry 53(2): 233-241, 2001

Femtosecond kinetics of electron transfer in the bacteriochlorophyll-M-modified reaction centers from Rhodobacter sphaeroides (R-26). FEBS Letters 383(1-2): 129-132, 1996

A gene from the photosynthetic gene cluster of rhodobacter sphaeroides induces trans suppression of bacteriochlorophyll and carotenoid levels in rhodobacter sphaeroides and rhodobacter capsulatus. Current Microbiology 23(5): 259-264, 1991

Investigation of the electron transfer reactions and redox characteristics of photoactive bacteriochlorophyll in Rhodobacter sphaeroides reaction centers modified by D2O and cryoprotectants. Membrane and Cell Biology 14(3): 343-356, 2000

Cu2+ site in photosynthetic bacterial reaction centers from Rhodobacter sphaeroides, Rhodobacter capsulatus, and Rhodopseudomonas viridis. Biochemistry (American Chemical Society) 40(20): 32-41, 2001

Cu 2+ Site in Photosynthetic Bacterial Reaction Centers from Rhodobacter sphaeroides , Rhodobacter capsulatus , and Rhodopseudomonas viridis. Biochemistry 40(20): 6132-6141, 2001

Changes in the oxidation potential of the bacteriochlorophyll dimer due to hydrogen bonds in reaction centers from Rhodobacter sphaeroides. Murata, N Research in photosynthesis, Vol 1; IXth International Congress on Photosynthesis: 377-380, 1992

Effects of hydrogen bonding to a bacteriochlorophyll-bacteriopheophytin dimer in reaction centers from Rhodobacter sphaeroides. Biochemistry 35(21): 6612-6619, 1996

Investigation of the electron transfer reactions and redox midpoint potential of photoactive bacteriochlorophyll in the reaction centers of Rhodobacter sphaeroides modified by D2O and cryoprotectants. Biologicheskie Membrany 17(3): 271-281, 2000

Characterization of mutants with altered hydrogen bonding to the bacteriochlorophyll dimer in reaction centers from Rhodobacter sphaeroides. Photochemistry and Photobiology 63(SPEC ISSUE): 51S-52S, 1996

Sulfhydryl modifying reagents inhibit q a negative oxidation in reaction centers from rhodobacter sphaeroides and rhodobacter capsulatus but not rhodopseudomonas viridis. Photosynthesis Research 26(3): 171-180, 1990

Study of wild type and genetically modified reaction centers from Rhodobacter capsulatus: structural comparison with Rhodopseudomonas viridis and Rhodobacter sphaeroides. Biophysical Journal 65(2): 652-660, 1993

Electrostatic interactions between charged amino acid residues and the bacteriochlorophyll dimer in reaction centers from Rhodobacter sphaeroides. Biochemistry (American Chemical Society) 40(50): 403-7, 2001

Correlation between Multiple Hydrogen Bonding and Alteration of the Oxidation Potential of the Bacteriochlorophyll Dimer of Reaction Centers from Rhodobacter sphaeroides. Biochemistry 34(18): 6142-6152, 1995

The membrane-bound cytochrome c-y of Rhodobacter capsulatus can serve as an electron donor to the photosynthetic reaction center of Rhodobacter sphaeroides. Biochimica et Biophysica Acta 1273(2): 159-164, 1996