Single-Myb-histone proteins from Arabidopsis thaliana: a quantitative study of telomere-binding specificity and kinetics
Single-Myb-histone proteins from Arabidopsis thaliana: a quantitative study of telomere-binding specificity and kinetics
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DOI：
10.1042/bj20082195
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发表时间：
2009-04-01
影响因子：
4.1
通讯作者：
Fajkus, Jiri
中科院分区：
文献类型：
--
作者：
Hofr, Ctirad;Sultesova, Pavla;Fajkus, Jiri
结合端粒 DNA 的蛋白质调节染色体末端的结构，帮助控制端粒功能和维持。研究表明，来自 SMH（单 Myb 组蛋白）家族的 AtTRB（拟南芥端粒重复结合因子）蛋白选择性结合双链端粒 DNA，并与参与端粒加帽的端粒蛋白 AtPOT1b（拟南芥端粒保护 1b）相互作用。在本研究中，我们对这种植物特异性蛋白质家族进行了首次定量 DNA 结合研究。通过电泳迁移率变动测定、荧光各向异性和表面等离子共振分析全长蛋白 AtTRB1 和 AtTRB3 与端粒 DNA 的相互作用，以揭示它们的结合化学计量和动力学。不同盐条件下的动力学分析使 LIS 能够估计结合的静电成分，并解释两种蛋白质与端粒 DNA 的不同亲和力。根据现有数据，提出了解释结合化学计量和端粒 DNA 上蛋白质排列的推定模型。
Proteins that bind telomeric DNA modulate the structure of chromosome ends,aid control telomere function and maintenance. It has been shown that AtTRB (Arabidopsis thaliana telomere-repeat-binding factor) proteins from the SMH (single-Myb-histone) family selectively bind double-stranded telomeric DNA and interact with the telomeric protein AtPOT1b (A. thaliana protection of telomeres 1b), which is involved in telomere capping. In the present study, we performed the first quantitative DNA-binding study of this plant-specific family of proteins. Interactions of full-length proteins AtTRB1 and AtTRB3 with telomeric DNA were analysed by electrophoretic mobility-shift assay, fluorescence anisotropy and surface plasmon resonance to reveal their binding stoichiometry and kinetics. Kinetic analyses at different salt conditions enabled LIS to estimate the electrostatic component of binding and explain different affinities of the two proteins to telomeric DNA. On the basis of available data, a putative model explaining the binding stoichiometry and the protein arrangement on telomeric DNA is presented.