Zanetti G, Merati G
Dipartimento di Fisiologia e Biochimica Generali, Italy.
Eur J Biochem. 1987 Nov 16;169(1):143-6. doi: 10.1111/j.1432-1033.1987.tb13591.x.
Ferredoxin has been effectively cross-linked to photosystem I complex by treatment of purified particles or thylakoids with N-ethyl-3-(3-dimethylaminopropyl)carbodiimide, a zero-length cross-linker which stabilizes protein-protein electrostatic interactions. Analysis of photosystem I polypeptide composition after such a treatment showed a specific decrease of the 20-kDa subunit and the appearance of a new component of about 42 kDa which was recognized by the anti-ferredoxin antibody. Cross-linking of ferredoxin to thylakoids allowed the membrane preparation to photoreduce cytochrome c without requiring exogenous ferredoxin, whereas photosystem I particles purified from treated thylakoids were inactivated in the NADP+ photoreduction activity. From these results, it can be inferred that the polypeptide of 20 kDa is the photosystem I subunit which interacts with ferredoxin during the photosynthetic electron transport.
通过用N-乙基-3-(3-二甲基氨基丙基)碳二亚胺处理纯化的颗粒或类囊体，铁氧化还原蛋白已有效地与光系统I复合物交联，N-乙基-3-(3-二甲基氨基丙基)碳二亚胺是一种零长度交联剂，可稳定蛋白质-蛋白质静电相互作用。对经过这种处理后的光系统I多肽组成的分析表明，20 kDa亚基有特异性减少，并且出现了一种约42 kDa的新组分，该组分可被抗铁氧化还原蛋白抗体识别。铁氧化还原蛋白与类囊体的交联使膜制剂能够在不需要外源铁氧化还原蛋白的情况下光还原细胞色素c，而从经处理的类囊体中纯化的光系统I颗粒在NADP+光还原活性方面失活。从这些结果可以推断，20 kDa的多肽是在光合电子传递过程中与铁氧化还原蛋白相互作用的光系统I亚基。
