Expression and pH-dependence of the Photosystem II Subunit S from Arabidopsis thaliana

Bulletin of the Korean chemical society

Ismayil S Zulfugarov¹  Yong Hwan Moon¹  Mi Suk Jeong¹  So Young Park¹  Se Bok Jang¹  Choon Hwan Lee¹  Eun Young Hwang¹  Gyoung Ean Jin¹ 

关键词: Photosystem II subunit S;    Expression;    pH dependence;    Temperature dependence;   

DOI  :  

学科分类：化学（综合）

来源: Korean Chemical Society

【 摘 要 】

Photosynthesis uses light energy to drive the oxidation of water at an oxygen-evolving catalytic site within photosystem II (PSII). Chlorophyll binding by the photosystem II subunit S protein, PsbS, was found to be necessary for energy-dependent quenching (qE), the major energy-dependent component of non-photochemical quenching (NPQ) in Arabidopsis thaliana. It is proposed that PsbS acts as a trigger of the conformational change that leads to the establishment of nonphotochemical quenching. However, the exact structure and function of PsbS in PSII are still unknown. Here, we clone and express the recombinant PsbS gene from Arabidopsis thaliana in E. coli and purify the resulting homogeneous protein. We used various biochemical and biophysical techniques to elucidate PsbS structure and function, including circular dichroism (CD), fluorescence, and DSC. The protein shows optimal stability at 4 ^oC and pH 7.5. The CD spectra of PsbS show that the conformational changes of the protein were strongly dependent on pH conditions. The CD curve for PsbS at pH 10.5 curve had the deepest negative peak and the peak of PsbS at pH 4.5 was the least negative. The fluorescence emission spectrum of the purified PsbS protein was also measured, and the �?_max was found to be at 328 nm. PsbS revealed some structural changes under varying temperature and oxygen gas condition.

【 授权许可】

Unknown