Service Biophysique, Département de Biologie, CEN Saclay, Gif-sur-Yvette, France
Abstract:
The light-harvesting complex and Photosystem I have been isolated from thylakoids of two chromophyte algae by digitonin solubilisation and sucrose-gradient centrifugation. The -helic and β-structure content was determined by ultraviolet circular dichroism. The values obtained were approx. 40% -helix and approx. 14% β-structure for the light-harvesting complex of both Pavlova lutherii and Phaeodactylum tricornutum. For Photosystem I the values were approx. 55% -helix and 7% β-structure for both algae. It is concluded that for all photosynthetic antennae containing chlorophyll the dominant secondary structure is -helix.