Biochemical and Immunochemical Investigations on the Light‐Harvesting System of the Cryptophyte Rhodomonas sp.: Evidence for a Photosystem I Specific Antenna

Abstract

Abstract: Thylakoid membranes of the cryptophyte Rhodomonas sp. were solubilized with the mild detergent dodecyl‐β‐maltoside and subjected to sucrose density gradient centrifugation. The resulting gradients showed six pigment‐bearing bands which were characterized further by means of absorption and fluorescence emission (77K) spectroscopy, polyacrylamide gel electrophoresis and Western immunoblotting. Two of the bands showed characteristics of light‐harvesting complexes, other bands could be attributed to photosystem II and photosystem I. Up to 10 different light‐harvesting proteins could be identified, some of which are specific for photosystem I, others for photosystem II. The polypeptides of the light‐harvesting complex of photosystem II show a higher chlorophyll c/a ratio than the antenna proteins of photosystem I. As in vascular plants, they represent the bulk of the membrane‐intrinsic light‐harvesting proteins.