
%0 Journal Article
%A Mangels, Dorothea 
%A Kruip, Jochen 
%A Berry, Stephan 
%A Roegner, Matthias 
%A Boekema, Egbert J 
%A Koenig, Friederikek 
%T Purification and characterisation of photosystem I from the unusual cyanobacterium
Gloeobacter violaceus
%J Science Access
%D 2001/01/01
%V 3
%N 1
%P -
%K 
%R https://doi.org/10.1071/SA0403624
%U https://www.publish.csiro.au/paper/SA0403624 
%X Photosystem I from the highly unusual primitive cyanobacterium Gloeobacter violaceus was purified. The isolated Photosystem I complexes have the same subunit composition as complexes from other cyanobacteria as determined by high resolution gel electrophoresis and immunoblotting. They exist both in a trimeric and in a monomeric form as shown by gel filtration and electron microscopy. Image analysis of single particles shows that the size and shape of the particles closely resembles other cyanobacterial Photosystem I particles. Flash induced absorption difference spectra show a classical P700 shape with kinetics and relaxation times similar to Photosystem I from Synechocystis, but its amplitude indicates a much bigger antenna size, resembling the spectra of higher plants rather than those of other cyanobacteria. 77 K fluorescence emission spectra lack the typical long wavelength emission peaks of cyanobacterial Photosystem I. In addition, the preparation contains novel polypeptides not related to known Photosystem I subunits. Immunoblotting shows the possible existence of a membrane intrinsic light-harvesting protein related to LHC proteins of Chromophytes. Moreover, electron microscopy reveals a novel T-shaped complex that has not been observed so far. 
