Fluorescence resonance energy transfer study of subunit exchange in human lens crystallins and congenital cataract crystallin mutants.
Fluorescence resonance energy transfer study of subunit exchange in human lens crystallins and congenital cataract crystallin mutants.
复制标题
人晶状体蛋白和先天性白内障晶状体蛋白突变体亚基交换的荧光共振能量转移研究。
DOI：
10.1110/ps.062216006
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
Liu,Bing-Fen
中科院分区：
文献类型：
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作者：
Liang,JackJ;Liu,Bing-Fen
透镜α-晶状体蛋白是分子量为500-1000 kDa的寡聚蛋白，并且是多分散的组装体。它由两种类型的亚基aA和aB组成，每个亚基的分子量为20 kDa。这些亚基也在一些其他组织和体外形成同源寡聚体。它们的四级结构，这是动态的，其特征在于亚基交换，已被研究了许多技术，包括荧光共振能量转移（FRET）和质谱分析。所提出的亚基交换机制是通过单体亚基的解离/缔合或通过寡聚体和亚寡聚体之间的快速平衡。为了进一步探索亚基交换的性质，我们进行了额外的FRET测量和分析，使用荧光染料标记的W 9 F aA-晶状体蛋白作为受体探针，其他晶状体蛋白（野生型和R116 C aA，野生型和R120 G aB，野生型和Q155* bB 2）中的Trp作为供体探针，并计算了转移效率，Förster距离和两个探针之间的平均距离。结果表明，尽管构象发生了变化，但对于R116 C aA和R120 G aB突变，两个探针之间的效率仅略有降低，距离增加。
Lens a-crystallin is an oligomeric protein with a molecular mass of 500–1000 kDa and a polydispersed assembly. It consists of two types of subunits, aA and aB, each with a molecular mass of 20 kDa. The subunits also form homo-oligomers in some other tissues and in vitro. Their quaternary structures, which are dynamic and characterized by subunit exchange, have been studied by many techniques, including fluorescence resonance energy transfer (FRET) and mass spectrometry analysis. The proposed mechanism of subunit exchange has been either by dissociation/association of monomeric subunits or by rapid equilibrium between oligomers and suboligomers. To explore the nature of subunit exchange further, we performed additional FRET measurements and analyses using a fluorescent dye-labeled W9F aA-crystallin as the acceptor probe and Trp in other crystallins (wild-type and R116C aA, wildtype and R120G aB, wild-type and Q155* bB2) as the donor probe and calculated the transfer efficiency, Förster distance, and average distance between two probes. The results indicate only slight decreased efficiency and increased distance between two probes for the R116C aA and R120G aB mutations despite conformational changes.