Nechushtai R, Schuster G, Nelson N, Ohad I
Eur J Biochem. 1986 Aug 15;159(1):157-61. doi: 10.1111/j.1432-1033.1986.tb09846.x.
Photosystem I reaction centers were isolated from mesophyll and bundle-sheath chloroplasts of the C4 maize plant. Both preparations were found to be free of chlorophyll b and to have the same spectral properties and chlorophyll/P700 ratio as photosystem I reaction centers isolated from C3 plants. Photosystem I reaction centers from both mesophyll and bundle sheath were found to consist of six subunits with apparent molecular masses of about 70 kDa, 20 kDa, 17 kDa, 16 kDa, 10 kDa and 8 kDa, corresponding to photosystem I reaction center subunits I, II, IV, V, VI and VII of spinach, as tested by their immunological cross-reactivity with antibody raised against the respective spinach subunits. No cross-reactivity was found with antibodies raised against subunit III of spinach, either in whole thylakoids or purified reaction centers of both bundle-sheath and mesophyll chloroplasts. It is concluded that photosystem I reaction centers of bundle-sheath and mesophyll thylakoids of maize are identical and lack the polypeptide corresponding to subunit III present in all C3 plants so far tested.
从C4玉米植株的叶肉和维管束鞘叶绿体中分离出光系统I反应中心。发现这两种制剂均不含叶绿素b，并且具有与从C3植物中分离出的光系统I反应中心相同的光谱特性和叶绿素/P700比率。通过与针对菠菜相应亚基产生的抗体的免疫交叉反应测试，发现叶肉和维管束鞘的光系统I反应中心均由六个亚基组成，其表观分子量约为70 kDa、20 kDa、17 kDa、16 kDa、10 kDa和8 kDa，分别对应菠菜光系统I反应中心亚基I、II、IV、V、VI和VII。在维管束鞘和叶肉叶绿体的整个类囊体或纯化的反应中心中，均未发现与针对菠菜亚基III产生的抗体有交叉反应。得出的结论是，玉米维管束鞘和叶肉类囊体的光系统I反应中心是相同的，并且缺少迄今为止测试的所有C3植物中存在的与亚基III相对应的多肽。
