Structure and function of a photoconvertible Water-soluble chlorophyll protein from Chenopodium album.

水溶性叶绿素结合蛋白参与叶绿素的生物合成，运输，和/或其降解过程已被预测。然而，此类研究尚未广泛开展。本研究从藜（Chenopodium album）中分离纯化了水溶性叶绿素蛋白（WSCP），并克隆了其cDNA，序列分析表明，该WSCP具有N端信号序列，成熟WSCP全长169个残基，其中C端加工区22个残基。同源性分析表明，该基因属于广泛分布于绿色植物中的DUF 538家族成员，并在大肠杆菌中得到表达。将重组WSCP分级分离成不溶性部分。用尿素变性蛋白质并随后进行复性。我们找到了一个可以恢复其叶绿素结合和光转换活性的条件，并制备了抗大肠杆菌表达的不溶性WSCP的多克隆抗体。分析WSCP的组织和亚细胞定位。WSCP定位于叶绿体的水溶性部分和类囊体膜部分，表明存在膜结合形式。转基因植株表现为部分不育，生长缓慢，进入生殖生长期缓慢。

Participation of water-soluble chlorphyll binding proteins during chlorophyll biosynthesis, transportation, and/or its degradation processes have been predicted. However, such studies have not been performed extensively. In this study, we purified the water-soluble chlorophyll protein(WSCP) from Chenopodium album and its cDNA was cloned.Sequence analysis of its cDNA revealed that the WSCP possess N-terminal signal sequence, mature-WSCP of 169 residues including 22 residues of C-terminal processed region. Homology analysis revealed that the WSCP is a member of DUF538 family that is a family wide spread in green plant.The WSCP was express in E.coli. The recombinant WSCP was fractionated into insoluble fraction. Denaturing of the protein with urea and following renaturation was performed. We found a acceptable condition for the recovery of its chlorophyll binding and photo-converting activities.The poly clonal antibody was raised aganst the E.coli-expressed insoluble WSCP. Tissue and subcellular localization of WSCP were analyzed. The WSCP located in water-soluble fraction and thylakoid membrane fraction of chloroplast indicating that existance of membrane-bound form.To investigate its physiological function, the transgenic Arabidopsis expressing WSCP were produced. Phenotype of the transgenic plants is partial sterile, slow glowth, slow entering into reproductive growth phase.