Properties of the low-temperature Photosystem I primary reaction in the P-700-chlorophyll a-protein

Contribution to the structural characterization of eucaryotic PSI reaction centre ? II. Characterization of a highly purified photoactive SDS-CP1 complex

“…Mathis et al [26] demonstrated that in these particles, a back reaction takes place between P700 ÷ and A~ (or A~) without previous reduction of acceptors. This last observation, made with flash laser spectroscopy, is consistent with Malkin's suggestion that electron acceptors of P700 are damaged or absent [25]. The other photochemical characteristics of these particles and the conditions under which they retain photochemical activity are being investigated.…”

“…Table 1 gives the photochemical properties of CPI and, for comparison, the properties of different preparations of PSI reaction centres. The ~i l i t y of [25] explained this absence of activity by a lack of iron-sulphur centres. A CP1 which retains P700 photoactivity at 77K, but with a low efficiency, has been isolated from higher plants [17].…”

“…Based on homologies of size, amino acids and pigments compositions of complex I and the P700-chla-protein complex from blue green 18 algae, Thornber postulated the presence of a common complex for all organisms exhibiting a PSI activity [35]. No photoactivity was observed in eucaryotic CP1 extracted with SDS PAGE [7,25,33], but a correlation was demonstrated between the activity of P700 and the occurrence of CP1 [34]. Since the use of SDS appeared to destroy photochemical activity in higher plants, other detergents were utilized for the isolation of reaction centres.…”

Membrane-bound iron-sulfur centers in photosynthetic systems

“…Studies involving subchloroplast fragments enriched in either the Photosystem I or Photosystem Ii reactIon center have 'confirmed the association of the bound iron-sulfur ceriter with Ph 0 tosy'stem 1 [9 ,i 0]. Various types of Photosystem I subchloroplast fragmen'ts (prepared with 'detergents or by the French pressure ceUmethod) have all shown the' presence of the bound-irod-sulfur center and it has been possible to dem,onstrate its ph\)toieductiori in these preparations [9][10][11][12][13]. As but one example, Fig.…”

Photobiological Production of Hydrogen: A Solar Energy Conversion Option

“…It may be a membrane-bound iron-sulfur protein, but alternative possibilities cannot be ruled out (Bolton, 1976;Malkin et al, 1976;--Heathcote et al, 1978;Sauer et al, 1978).…”