Schuster G, Ohad I, Martineau B, Taylor W C
J Biol Chem. 1985 Sep 25;260(21):11866-73.
Photosynthetic electron flow, polypeptide pattern, presence of chlorophyll-protein complexes, and phosphorylation of thylakoid polypeptides have been investigated in differentiated mesophyll (M) and bundle sheath (B) thylakoids of the C4 plant Zea mays. The polypeptide pattern of M thylakoids and their photosynthetic electron flow are comparable to those of other green plants. B thylakoids exhibit only photosystem I (PSI) activity, contain only traces of the PSII light harvesting (LHCII) polypeptide, do not bind [3H] diuron, and lack polypeptides of the water-oxidation complex of PSII and the herbicide binding 32-kDa polypeptide, as detected by specific antibodies. However, B thylakoids possess a partially active PSII reaction center, as demonstrated by light-dependent reduction of silicomolybdate with 1,5-diphenylcarbazide (DPC) as an electron donor, and the presence of the PSII reaction center polypeptides of 44-47 kDa. Only one chlorophyll a-protein complex, corresponding to the PSI reaction center-core antenna, was detectable in B thylakoids, as opposed to chlorophyll a and chlorophyll a,b-protein complexes present in M thylakoids. The light-dependent, membrane-bound kinase activity present in M thylakoids could not be detected in B thylakoids which, nevertheless, contain a protein kinase able to phosphorylate casein. A total of 19 differences between the electrophoretic pattern of B and M thylakoid polypeptides were observed. The mRNA coding for the LHCII polypeptide is primarily, if not exclusively, localized in M cells. The development of PSII complex precedes that of PSI during the differentiation of B and M chloroplasts in expanding leaves of light-grown plants and during the greening of dark-grown etiolated seedlings. The differentiation of the maize leaf into cells programmed to form B or M chloroplasts does not require light. In light-grown plants, the differentiation of B and M thylakoids occurred progressively from the base of the leaf and was completed at 4-5 cm from the leaf base.
对C4植物玉米分化的叶肉（M）和维管束鞘（B）类囊体中的光合电子流、多肽模式、叶绿素-蛋白复合体的存在以及类囊体多肽的磷酸化进行了研究。M类囊体的多肽模式及其光合电子流与其他绿色植物相当。B类囊体仅表现出光系统I（PSI）活性，仅含有痕量的PSII捕光（LHCII）多肽，不结合[3H]敌草隆，并且缺乏PSII水氧化复合体的多肽和除草剂结合的32 kDa多肽，这是通过特异性抗体检测到的。然而，B类囊体具有部分活性的PSII反应中心，以1,5-二苯基卡巴腙（DPC）作为电子供体，通过硅钼酸盐的光依赖性还原以及44-47 kDa的PSII反应中心多肽的存在证明了这一点。与M类囊体中存在的叶绿素a和叶绿素a,b-蛋白复合体相反，在B类囊体中仅可检测到一种对应于PSI反应中心-核心天线的叶绿素a-蛋白复合体。在M类囊体中存在的光依赖性膜结合激酶活性在B类囊体中未检测到，不过B类囊体含有一种能够使酪蛋白磷酸化的蛋白激酶。观察到B和M类囊体多肽的电泳模式之间共有19处差异。编码LHCII多肽的mRNA主要（如果不是唯一地）定位于M细胞中。在光照生长植物的展开叶片中B和M叶绿体的分化过程以及黑暗生长的黄化幼苗的绿化过程中，PSII复合体的发育先于PSI。玉米叶片分化为编程形成B或M叶绿体的细胞不需要光照。在光照生长的植物中，B和M类囊体的分化从叶基部开始逐渐发生，并在距叶基部4-5厘米处完成。
