结合态PC645组分的分离纯化和性质  

Isolation and Characterization of PC645 in Binding State from Chroomonas placoide

作　　者：王宇涵 任靖文 陈敏[1] WANG Yuhan;REN Jingwen;CHEN Min(School of Life Sciences,Yantai University,Yantai 264005,China)

机构地区：[1]烟台大学生命科学学院,山东烟台264005

出　　处：《烟台大学学报（自然科学与工程版）》2024年第3期281-292,共12页Journal of Yantai University(Natural Science and Engineering Edition)

基　　金：山东省自然科学基金资助项目(ZR2018LD009)。

摘　　要：采用蔗糖密度梯度离心方法从蓝隐藻(Chroomonas placoidea)中分离得到了含有结合态藻蓝蛋白PC645的Chl-蛋白条带BandⅢ;硫酸铵分级沉淀显示,50%硫酸铵可最有效去除其中大部分Chl-蛋白且有效避免PC645的损失。光谱和多肽分析表明,含量最丰富的BandⅠ的亚基主要为1型,说明PC645占主导的α1α2β1β2异二聚体形式主要以游离态存在于类囊体腔中;而BandⅢ中富含的2型亚基参与形成的异二聚体很可能为α1α2β1β2,其疏水性更强,更易于被盐析沉淀。硫酸铵分级沉淀后的BandⅢ经疏水层析得到的疏水程度较低的组分1同时含有PC645和Chl a-蛋白;疏水程度最高的组分4,为基本不含叶绿素的、充分纯化的PC645,且很可能是BandⅢ中与Chl-蛋白处于结合态的PC645组分。结果为今后隐藻两套捕光系统结构和相互作用机制研究奠定了基础。A Chl-protein band named BandⅢcontaining phycocyanin PC645 in binding state is isolated frm Chroomonas placoidea by using the method of sucrose density gradient centrifugation.The results of ammonium sul.fate fractionation show that 5096 ammonium sulfate precipitation can remove most of the Chl-protein complexes in BandⅡand effectively avoid the loss of PC645.Spectral and peptide analysis demonstrate that the subunit type of the most abundant band BandⅠisβ_(1),indicating that theα_(1)α_(2)β_(1)β_(1),heterodimer form predominated in PC645 is mainly free in the thylakoid lumen.While,the heterodimer containing 2 subunit enriched in Band ll is probablyα_(1)α_(2)β_(1)β_(2),which exhibits higher hydrphobicity and therefore more susceptible to be salted out.BandⅡafter am.monium sulfate fractionation is subject to hydrophobic chromatography.The eluted fraction 1 with relatively lower hydrophobicity contains both PC645 and Chl a-protein.The eluted fraction 4 with relatively highest hydrophobicity is recognized as fully purified PC645 containing almost no chlorophyll,and most likely the PC645 component of BandⅢin binding state to Chl-prtein.These results lay a foundation for structure and interaction studies between the two sets of light-harvesting systems in cryptophytic algae in the future.

关 键 词：蓝隐藻 PC645-Chl-蛋白复合物 蔗糖密度梯度离心 硫酸铵分级沉淀 疏水层析 

分 类 号：Q946[生物学—植物学]