Henry R L, Armbrust T, Gallegos G, Guikema J A
Center for Gravitational Studies in Cellular and Developmental Biology, Kansas State University, Manhattan, USA.
Plant Physiol Biochem. 1992;30(3):347-56.
The structure and supramolecular assembly of the soybean photosystem 1 (PS 1) chlorophyll a/b-binding antenna (LHC 1) was examined. We identified the subunit composition of LHC 1 in soybean and followed the accumulation of individual subunits during light-induced assembly. We observed four LHC 1 subunits, at 23, 22, 21 and 20.5 kDa, obtained partial sequence information by amino-terminal sequence analysis, and classified the 20.5, 22, and 21 kDa subunits as being encoded by type I, II, and IV chlorophyll a/b binding protein genes, respectively. Antisera against LHC 1 subunits were used to follow the accumulation of individual subunits during the light-initiated transition from etioplast to chloroplast. Several points are noteworthy. First, monospecific antibody against the 22 kDa subunit decorated a 25 kDa peptide in etiolated tissue, which declined during maturation. This decline correlated with the light-induced appearance of mature 22 kDa peptide, suggesting a precursor/product relationship. Second, the same antibody identified a 22 kDa protein in mature corn, but not a larger band in etiolated corn, suggesting that LHC 1 accumulation is regulated differently between species before the onset of chlorophyll biosynthesis. Third, the mature 22 kDa subunit appeared somewhat later than the other LHC 1 peptides during greening, implying that this subunit is less intimately associated with the PS1 core than are the subunits appearing earlier in development.
对大豆光系统1（PS1）叶绿素a/b结合天线（LHC1）的结构和超分子组装进行了研究。我们确定了大豆中LHC1的亚基组成，并追踪了光诱导组装过程中各个亚基的积累情况。我们观察到四个LHC1亚基，分子量分别为23、22、21和20.5 kDa，通过氨基末端序列分析获得了部分序列信息，并将20.5、22和21 kDa的亚基分别归类为由I型、II型和IV型叶绿素a/b结合蛋白基因编码。利用针对LHC1亚基的抗血清追踪从黄化质体到叶绿体的光启动转变过程中各个亚基的积累情况。有几点值得注意。首先，针对22 kDa亚基的单特异性抗体在黄化组织中识别出一种25 kDa的肽段，该肽段在成熟过程中减少。这种减少与光诱导出现的成熟22 kDa肽段相关，表明存在前体/产物关系。其次，相同的抗体在成熟玉米中识别出一种22 kDa的蛋白质，但在黄化玉米中未识别出更大的条带，这表明在叶绿素生物合成开始之前，不同物种之间LHC1的积累调控方式不同。第三，在绿化过程中，成熟的22 kDa亚基比其他LHC1肽段出现得稍晚，这意味着该亚基与PS1核心的关联不如发育早期出现的亚基紧密。
