EurekaMag.com logo
+ Site Statistics
References:
53,214,146
Abstracts:
29,074,682
+ Search Articles
+ Subscribe to Site Feeds
EurekaMag Most Shared ContentMost Shared
EurekaMag PDF Full Text ContentPDF Full Text
+ PDF Full Text
Request PDF Full TextRequest PDF Full Text
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter
Follow on Google+Follow on Google+
Follow on LinkedInFollow on LinkedIn

+ Translate

Spectral and photochemical properties of photosynthetic reaction center preparations from rhodopseudomonas sphaeroides strain 1760 1






Studia Biophysica 55(3): 183-198

Spectral and photochemical properties of photosynthetic reaction center preparations from rhodopseudomonas sphaeroides strain 1760 1

Photosynthetic reaction centers [RCs] were isolated from R. sphaeroides cells, strain 1760-1 by means of SDS [sodium dodecyl sulfate] as a detergent. The absorption indices of the preparations purified by precipitation with (NH4)2SO4 are A280:A800 = 2.1 and A760:A800:A870 = 1:2:1; at least 75% of BChl [bacteriochlorophyll] absorbing at 870 nm are photochemically active. Absolute and light-minus-dark absorption spectra of RC suspensions and vacuum-dried films were obtained both at room and low temperatures. The red-shift of the 870 -nm band observed with temperature lowering was explained in terms of the temperature-determined conformations of the pigment-protein complex of the reaction centers. As calculated on the basis of the measurements made by laser flash fluorometric technique, the time needed for electron transfer from photoexcited [BChl] P870 to the primary intermediate (Ai) of photochemical reaction is (21-15).+-. 8 ps. By analysis of the temperature dependence of P870 recovery after its photooxidation induced by a single laser pulse estimates were made of the rate constant KA1A2 for electron transfer from A1 to the secondary electron acceptor (A2) at different temperatures. At 300.degree. K the half-time for this reaction (t1/2) is 710 .mu.s. Over the temperature range of 270-230.degree. K, KA1A2 is exponentially dependent on temperature (Eact. [activation energy] = 10.8 kcal/mol), but at temperatures between 210-180.degree. K it does not vary measurably (Eact. < 0.8 kcal/mol). The ty2 is 45 ms for the recombination of the primary photochemical products, P870+ and A1, at 120.degree. K. Dependence of the kinetic behavior of P870 dark reduction on the intensity of steady light illumination indicates the presence of the heterogeneous pool of secondary acceptors in RC preparations, the filling of which is limited at low temperatures and upon vacuum-drying and the electron capacity of which is confined on extracting ubiquinones.

(PDF 0-2 workdays service: $29.90)

Accession: 006459518



Related references

Isolation and investigation of photochemical properties of photosynthetic reaction centers from rhodopseudomonas sphaeroides strain 1760 1. Molecular Biology (English Translation of Molekulyarnaya Biologiya (Moscow)) 10(3): 526-534, 1976

Isolation and characterization of photochemical properties of the photosynthetic reaction centers from rhodopseudomonas sphaeroides strain 1760 1. Molekulyarnaya Biologiya (Moscow) 10(3): 641-651, 1976

Study of temperature dependence of the kinetics of dark reduction of bacterio chlorophyll p 870 oxidized by pulsed laser and continuous light in photosynthetic reaction center preparations from rhodopseudomonas sphaeroides strain 1760 1. Biofizika 21(2): 300-306, 1976

Investigation of the temperature dependence of the kinetics of the dark reduction of bacterio chlorophyll p 870 oxidized with pulsed laser and constant light in preparations of the photosynthetic reaction centers of rhodopseudomonas sphaeroides strain 1760 1. Biophysics (English Translation of Biofizika) 21(2): (1977), 1976

Electric field-induced polarization of photosynthetic membranes and reaction centers of Rhodopseudomonas sphaeroides, strain 1760-1. Acta Biochimica et Biophysica; Academiae Scientiarum Hungaricae 13(1-2): 67-72, 1978

Polarization of photosynthetic membranes and reaction centers of Rhodopseudomonas sphaeroides 1760-1 in an external electrical field. Biofizika 24(5): 843-848, 1979

Polarization of photosynthetic membranes and the reaction centers of rhodopseudomonas sphaeroides 1760 1 in an external electric field. Biophysics (English Translation of Biofizika) 24(5): 862-867, 1979

Probing the fluorescence emission kinetics of the photosynthetic apparatus of Rhodopseudomonas sphaeroides, strain 1760-1, on a picosecond pulse fluorometer. Biochimica et Biophysica Acta 461(3): 403-412, 1977

Photochemical properties and energy transfer in reaction center preparations of rhodopseudomonas spheroides. Forti, Giorgio, Mordhay Avron And Andrea Melandri (Ed ) Photosynthesis, Two Centuries After Its Discovery By Joseph Priestley Proceedings Of The 2nd International Congress on Photosynthesis Research, Vol 1 Stresa, Italy June 24-29, 1971 Xxiii+860p Illus Dr W Junk N V : The Hague, The Netherlands 373-382, 1972

Spectral properties of reaction center preparations from Rhodopseudomonas spheroides. Journal of Biological Chemistry 248(9): 3041-3045, 1973