Mühlenhoff U, Zhao J, Bryant D A
Department of Biochemistry and Molecular Biology, The Pennsylvania State University, USA.
Eur J Biochem. 1996 Jan 15;235(1-2):324-31. doi: 10.1111/j.1432-1033.1996.00324.x.
The interaction between photosystem I (PS I) and flavodoxin from the cyanobacterium Synechococcus sp. PCC 7002 was investigated by covalent cross-linking in the presence of a hydrophilic cross-linker, N- ethyl-3-(3-diaminopropyl)carbodiimide. Under the experimental conditions employed, five distinct cross-linking products of flavodoxin and PS I subunits are formed. Immunoblot analyses show that these species are the result of cross-linking of flavodoxin to PsaC, PsaD, an unidentified low-molecular-mass PS I polypeptide, and a 15-kDa subunit. The latter has been indirectly identified as the PsaF subunit. Analysis of the interaction of flavodoxin with PS I from a psaE mutant indicates that the PsaE subunit is required for correct complex formation between flavodoxin and PS I, although this subunit is not directly cross-linked to flavodoxin. In addition, the cross-linking products of PsaD with PsaC and PsaL, and PsaE with PsaF, are observed. The covalent complex of flavodoxin and PS I is shown to be fully inhibited with respect to electron transfer to soluble flavodoxin, ferredoxin or ferredoxin:NADP+ oxidoreductase.
利用亲水性交联剂N-乙基-3-(3-二氨基丙基)碳二亚胺，通过共价交联对来自聚球藻属嗜热蓝细菌PCC 7002的光系统I（PS I）与黄素氧还蛋白之间的相互作用进行了研究。在所采用的实验条件下，形成了五种不同的黄素氧还蛋白与PS I亚基的交联产物。免疫印迹分析表明，这些产物是黄素氧还蛋白与PsaC、PsaD、一种未鉴定的低分子量PS I多肽以及一个15 kDa亚基交联的结果。后者已间接鉴定为PsaF亚基。对来自psaE突变体的黄素氧还蛋白与PS I相互作用的分析表明，尽管PsaE亚基不直接与黄素氧还蛋白交联，但它是黄素氧还蛋白与PS I之间正确形成复合物所必需的。此外，还观察到了PsaD与PsaC和PsaL以及PsaE与PsaF的交联产物。结果表明，黄素氧还蛋白与PS I的共价复合物在向可溶性黄素氧还蛋白、铁氧还蛋白或铁氧还蛋白：NADP⁺氧化还原酶的电子转移方面完全受到抑制。
