New evidence suggests that the initial photoinduced cleavage of the D1‐protein may not occur near the PEST sequence

FEBS Letters

Barbato, Roberto²  Giacometti, Giorgio M.²  Barber, James¹  Shipton, Catherine A.¹ 

[1] AFRC Photosynthesis Research Group, Wolfson Laboratories, Biochemistry Department, Imperial College of Science, Technology and Medicine, London SW7 2AY, UK;Dipartimento di Biologia, Universita' di Padova, Via Trieste 75, 35121, Padova, Italy

关键词: Photosynthesis;    Photosystem 2;    D1-polypeptide;    Photoinhibition;    Chl;    chlorophyll;    DBMIB;    2;    5-dibromo-3-methyl-6-isopropyl-p-benzoquinone;    PSII;    photosystem 2;    RC;    reaction centre;    SDS;    sodium dodecyl sulphate;   

DOI  :  10.1016/0014-5793(91)81250-C

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

When isolated reaction centres of photosystem 2 from pea or wheat are exposed to photoinhibitory illumination in the presence of an electron acceptor, breakdown products of the D1-protein are observed having molecular masses ranging from about 24 to 10 kDa. By using antibodies raised to the C-terminal or N-terminal portions of D1 it was shown that the major breakdown fragment of 24 kDa was derived from the C-terminus. This conclusion was supported by phosphorylation studies and from the digestion pattern obtained by lysine specific endoprotease-induced proteolysis. The complementary N-terminal breakdown fragment was found to have an apparent molecular mass of 10 kDa. The implications of these data are discussed in terms of the possible relationship between the 24 kDa C-terminal fragment and the 23.5 kDa breakdown fragment detected in vivo by Greenberg et al. [1987, EMBO J. 6, 2865–2869] and it is suggested, based on limited proteolysis using papain, that the latter may not be derived from the N-terminus as previously thought but also originates from the C-terminus.

【 授权许可】

Unknown