Two sites of primary degradation of the D1-protein induced by acceptor or donor side photo-inhibition in photosystem II core complexes.
Depending on experimental conditions we have found that photo-inhibitory treatment of photosystem II (PSII) core complexes, isolated from wheat, can generate two fragments of about 23-24 kDa that contain either the C-terminal or N-terminal regions of the D1-protein. A 24 kDa C-terminal fragment appears when the water splitting reaction is not functional and an electron acceptor is present. This 'donor'-side inhibition also generates an N-terminal fragment of about 10 kDa and is suggested to be due to the cleavage of a peptide bond in the region connecting transmembrane segments I and II of the D1-protein. In contrast, an N-terminal 23 kDa D1-protein fragment is detected when the water splitting reactions of the isolated complex are active, and occurs in the absence of an added electron acceptor. This 'acceptor'-side photo-inhibition also generates a C-terminal fragment of about 10 kDa.
De Las Rivas
J
J
Biochemistry Department, Wolfson Laboratories, Imperial College of Science, Technology and Medicine, London, UK.
Andersson
B
B
Barber
J
J
D000595:Amino Acid Sequence; D001345:Autoradiography; D015153:Blotting, Western; D008027:Light; D008969:Molecular Sequence Data; D045322:Photosynthetic Reaction Center Complex Proteins / Q000378:metabolism* / Q000528:radiation effects; D045332:Photosystem II Protein Complex; D010940:Plant Proteins / Q000378:metabolism*
D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D010940:Plant Proteins