clear-native PAGE, PSI supercomplex, fluorescence spectra at 77 K, MS analysis, 2D SDS

Various native CPCs from tylakoid membranes of plants are usually isolated using non-ionic detergents with subsequent centrifugation in sucrose gradient or with PAGE. So far, the supercomplex that contains both PSI with its LHCI and antenna complexes of PSII has been separated only by the centrifugation procedure. In our work, we present for the first time the separation of this supercomplex by native electrophoresis. The use of CNPAGE with deoxycholate as the additional charging component and fine adjustment of dodecylmaltoside/chlorophyll ratio and pH of electrode buffers allowed to separate the intact PSI supercomplexes. The polypeptide composition of the supercomplexes was determined by SDS-PAGE. The intactness of the supercomplexes was tested by the measurement of chlorophyll emission spectrum at 77K. The appearance of the PSI emission band with the maximum at 740 nm indicated that the LHCI-PSI connection is the same as in intact leaves.