Stoichiometry and turnover of photosystem II polypeptides

FEBS Letters

Barber, James¹  Gounaris, Kleoniki¹  Pick, Uri¹ 

[1] AFRC Photosynthesis Research Group, Department of Pure and Applied Biology, Imperial College of Science and Technology, London SW7, England

关键词: Photosystem II;    Detergent fractionation;    Photosynthesis;    Polypeptide;    Stoichiometry;    (Dunaliella salina);    SDS-PAGE;    SDS-polyacrylamide gel electrophoresis;    Mes;    (2-(N-morpholino)ethanesulphonic acid;   

DOI  :  10.1016/0014-5793(87)81281-4

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Using Triton X-100 solubilization and sucrose gradient fractionation, a photosystem II core complex has been isolated from the green alga Dunaliella salina. The complex was similar to that previously isolated from spinach [(1985) FEBS Lett. 188, 68-72] being composed of five main polypeptides of apparent molecular masses, 47, 40, 32, 30 and 10 kDa. Studies using ¹⁴C indicate that with either dark or illuminated cells the Stoichiometry of these polypeptides is 1:1:1:1:1 with about 20 chlorophyll a molecules per monomeric unit. According to ³⁵S labelling only the 32 kDa polypeptide, identified as the D1 or Q_B binding protein by immunoblotting, is rapidly turning over at a rate greater than the growth rate. The level of labelled sulphur associated with each polypeptide is reasonably consistent with the amino acid content derived from gene sequences and identifies the 47, 40, 32, 30 and 10 kDa apoproteins as products of the psbB, psbC, psbA, psbD and psbE genes.

【 授权许可】

Unknown