Energy conversion in the functional membrane of photosynthesis. Analysis by light pulse and electric pulse methods: The central role of the electric field

6 – Chlorophyll Fluorescence: An Intrinsic Probe of Photosynthesis

http://www.tau.ac.il/lifesci/courses/membrans/psistructure.pdf

Structure of photosystem I.

Difference spectra and extinction coefficients of P700

Coupling of quanta, electrons, fields, ions and phosphorylation in the functional membrane of photosynthesis. Results by pulse spectroscopic methods

The action of two chlorophyll-aI-molecules in light reaction I of photosynthesis.

main proteinaceous mass is gathered in regions at top and bottom of the mass-centre. These regions of high electron density within the mass-centre in Fig. i are symbolized by two discs each of about I0 fit of height and about 27 A of diameter ~la, c, 81. I t was also found that the mass-centres, which represent macromolecules of a few hundred atoms, form microcrystals within the protein layer, identical in size and shape. Each microcrystal (\"crystallite\") El] is built up of t 6 mass-centres arranged in a quadratic lattice. The dimensions of the crystallite are t65 A • t65 A • 36 A [21. In the lipoprotein lamellae of chloroplasts these crystallites represent the dominant part of the protein component of quantasomes E4~. Besides the crystallite each quantasome consists of enzyme protein particles attached to the crystallite [51 and of two further layers, namely a pigment layer (\"porphyrinring layer\") and a lipid layer (\"layer of the hydrocarbon chains\") [lb, c~. These results were found by previous evaluations of small angle x-ray diagrams and by the interpretation of electron micrographic pictures. In this paper more details about the mass-centres are given by the application of a method for the precise evaluation of discontinuous small angle x-ray diagrams obtained from micro crystals such as the crystallites [6, 7]. By this method it will be possible to determine the three-dimensional electron density of the tertiary structure of the mass-centres within tile crystallite.

W. Kreutz

Papers

The action of two chlorophyll-aI-molecules in light reaction I of photosynthesis.

On the tertiary structure of the protein layers of chloroplasts

About the proteinstructure of qantasomes