Mapping of two tyrosine residues involved in the quinone‐ (QB) binding site of the D‐1 reaction center polypeptide of photosystem II

FEBS Letters

Oettmeier, Walter¹  Meyer, Helmut E.²  Dostatni, Ralf¹ 

[1] Lehrstuhl Biochemie der Pflanzen, Ruhr-Universität, Postfach 10 21 48, D-4630 Bochum 1, FRG;Institut für Physiologische Chemie Ruhr-Universität, Postfach 10 21 48, D-4630 Bochum 1, FRG

关键词: Photoaffinity label;    Herbicide binding;    Amino acid sequence;    Photosystem II;    Protein D-1;   

DOI  :  10.1016/0014-5793(88)80918-9

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The property of the D-1 subunit of photosystem II in binding herbicides in its quinone-binding niche has provided important approaches to study its structure and function. In the D-1 protein, amino acid residues Tyr-254 and Tyr-237 are labeled by an [¹⁴C]azido-urea derivative, as identified by protein sequencing of proteolytic fragments. Whereas Tyr-254 is in a parallel α-helix already indicated to contribute to the herbicide-binding site, Tyr-237 is in a hydrophilic sequence that is partly accessible from the matrix space of the chloroplasts. This area has been implicated to contain a cleavage site for a protease involved in the rapid turnover of the D-1 polypeptide. The photoaffinity labeling results show that some of the amino acids in this cleavage site are actually part of the quinone-binding niche. It allows a refined and extended prediction of the three-dimensional folding of the reaction center of photosystem II.

【 授权许可】

Unknown