Reaction center isolation

Satoh, K. (1996). Introduction to photosystem II reaction center Isolation and biochemical and biophysical characterization. In D.R. Qrt and C.F. Yocum, eds., Oxygenic Photosynthesis. Boston Kluwer, pp. 193-212. 

Heathcote, P. and Clayton, R.K. 1977. Reconstituted energy transfer from antenna pigment-protein to reaction centers isolated from Rhodopseudomonas sphaeroides. Biochim. Biophys. Acta, 459. 506-515. 

Van der Rest, M. and Gingras, G. 1974. The pigment complement of the photosynthetic reaction center isolated from Rhodospirillum rubrum. J. Biol. Chem., 249,6446-6453. 

Fig. 1. Kinetics and standard free energy changes of electron transfer steps in reaction centers isolated from Rb. sphaeroides. In the chromatophore membrane, a c-type cytochrome (Cyt c,) normally reduces before an electron moves from Qa to Qg. The cytochrome oxidation has a time constant of about 20 fis in Rb. sphaeroides. and 0.5 to 2 p in reaction centers of Rp. viridis and Ch. vinosum, which have bound cytochromes. When the reaction center is excited a second time, Ob" is reduced to...

In addition to the L, M and H subunits, reaction centers isolated from Rp. vir-... 

Reaction centers isolated from the Rhodospirillaceae contain four molecules of BChl, two molecules of BPh, one or two quinones (depending on the isolation procedure), and one atom of nonheme Fe [21, 116]. As mentioned above, the quinones can be either ubiquinone or menaquinone, depending on the species. The Fe can be replaced by Mn, Zn or other metals with only minor effects on photochemical activity [42,117,118]. In reaction centers from Rp. viridis the BChl and... 

BPh are BChl b and BPh b in most of the other species that have been characterized, they are BChl a and BPh a. (BChl b differs from BChl a in having a vinyl group on ring II in place of an ethyl group. Thiocapsa pfennigii, another bacterial species that contains BChl b, resembles Rp.viridis in its photochemical activities [119,171].) Reaction centers isolated from Cf. aurantiacus are unusual in having three molecules of BChl a and three of BPh a, instead of four BChls and two BPhs [46,93]. 

The optical absorption spectrum of reaction centers isolated from the carotenoidless strain R-26 of Rb. sphaeroides has major bands near 530, 545, 600, 760, 800 and 880 nm (Fig. 5). There also is a set of strong, overlapping absorption bands... 

Figure 1 Absorption spectra of a suspension of purified reaction centers isolated from...

Figure 1 shows the absorption spectra recorded at room temperature and at lOK for a suspension of reaction centers isolated from the thermophilic species of R. sulfoviridis. Very similar spectra are obtained from the mesophilic species (data not shown). In the near infrared region, the general features of the absorption spectrum of the reaction centers of R. viridis (3) are observed for the R. sulfoviridis species ... 

These curves display the biphasicity of the charge recombination. At 832.5 nm, the decay is essentially exponential with the "slow" time constant tsiow = 1/ksiow = 2.2 ms. At 834 nm, however, the absorbance changes related to P+Qa is negative and decays with the "fast" time constant Xfast = 1/kfast = 0-54 ms. At 833 nm both components are present, but with opposite contributions to the absorbance change. This figure is similar to that measured by Sebban and Wraight [16] for the reaction centers isolated in detergent. 

Bacterial Growth and Reaction Center Isolation. U43 conjugants expressing either wild type (pU2922) or mutant (pAT-3) reaction center genes were grown semi aerobically in RCV+ medium and chromatophores or reaction centers were isolated by a modification of procedures described previously (Bylina and Youvan, 1988 Prince and Youvan, 1987). 

Reaction Center Isolation and Spectral Properties. Reaction centers can be isolated from pAT-3 containing 1. caps ul at us with yields comparable to, but somewhat lower than, that obtained from wild type cells. The room temperature and low temperature spectra of pAT-3 reaction centers are shown in Figs. 3 and 4. At room temperature, there is very little difference between the two spectra except that the Qy band of P (the special pair of the mutant) has a somewhat different shape than that of P in the wild type (Fig. 3). At 77K, these spectral... 

Recently we improved the reaction center isolation procedure - A purified preparation still containing the H subunit, and displaying a stable photochemical activity, was obtained - In this article we will compare some functional properties of this reaction center preparation with reference to Rhodopseudomonas viridis and Rhodobacter sphaeroides. Similarities are found with the former at the level of the acceptor quinone complex the structure of the primary donor in both the reduced and oxidized states, as determined by Fourier transform resonance Raman spectroscopy, resembles the latter. 

Figure 1 The polypeptide composition of photosystem I reaction center, isolated from Mastigocladus, Chlamydomonas and Swiss chard.

Nelson 1983). Antibodies against the individual subunits of photosystem I reaction center isolated from spinach or Swiss-chard were raised in rabbits as previously described (Nelson 1983). 

---