'Indirect Readout' Mediation of Protein-DNA Interactions

蛋白质-DNA 相互作用的“间接读出”介导

基本信息

批准号：
6797138
负责人：
Michael D. Brenowitz
金额：
$ 25.65万
依托单位：
ALBERT EINSTEIN COLLEGE OF MEDICINE
依托单位国家：
美国
项目类别：
财政年份：
2001
资助国家：
美国
起止时间：
2001-09-01 至 2006-08-31
项目状态：
已结题

项目摘要

The ability of proteins to recognize and bind specific sequences of DNA is a critical part of cellular function and regulation. Extensive structural and thermodynamic studies have yielded a general understanding of how direct contacts mediate the sequence-specific binding of proteins to DNA. However, subtle differences in DNA structure and dynamics often play critical roles in mediating the protein-DNA interactions that regulate many cellular processes by mechanisms independent of direct protein-DNA contacts. A regulatory system utilizing such an indirect control mechanism is the sequence-specific DNA binding by the papillomavirus E2 proteins. The E2 protein maintains a fine balance between replication and gene transcription that is essential for the viral life cycle; infection by some human papillomavirus strains is directly linked to cervical cancer. The regulation of papillomavirus replication and viral gene transcription is dependent upon E2 protein binding to an array of sites within viral genomes. The structure and dynamics of the DNA located within E2 protein binding sites is a principal determinant of protein binding affinity. The proposed studies use the E2 protein-DNA interaction as a model system to determine the mechanism by which local DNA structure and dynamics regulates sequence-specific binding. The foundation for the proposed thermodynamic and structural studies is the ensemble of atomic resolution structures of free protein, free DNA and protein-DNA complexes for the E2 family of evolutionarily related proteins that differ in their sensitivity to DNA structure and dynamics. The availability of these structures provides a unique opportunity to develop quantitative structure-function correlations regarding the indirect effect of conformational propensities of DNA upon protein binding in a context where direct protein-DNA interactions are kept constant.

蛋白质识别和结合特定 DNA 序列的能力是细胞功能和调节的关键部分。广泛的结构和热力学研究已经对直接接触如何介导蛋白质与 DNA 的序列特异性结合产生了总体了解。然而，DNA 结构和动力学的细微差异通常在介导蛋白质-DNA 相互作用中发挥关键作用，而蛋白质-DNA 相互作用通过独立于蛋白质-DNA 直接接触的机制来调节许多细胞过程。利用这种间接控制机制的调节系统是乳头瘤病毒 E2 蛋白的序列特异性 DNA 结合。 E2蛋白在复制和基因转录之间保持良好的平衡，这对于病毒的生命周期至关重要；某些人乳头瘤病毒株的感染与宫颈癌直接相关。乳头瘤病毒复制和病毒基因转录的调节取决于 E2 蛋白与病毒基因组内一系列位点的结合。位于 E2 蛋白结合位点内的 DNA 的结构和动力学是蛋白结合亲和力的主要决定因素。拟议的研究使用 E2 蛋白-DNA 相互作用作为模型系统来确定局部 DNA 结构和动力学调节序列特异性结合的机制。所提出的热力学和结构研究的基础是进化相关蛋白质 E2 家族的游离蛋白质、游离 DNA 和蛋白质-DNA 复合物的原子分辨率结构的集合，这些蛋白质对 DNA 结构和动力学的敏感性不同。这些结构的可用性提供了一个独特的机会，可以在蛋白质-DNA 直接相互作用保持恒定的情况下，开发关于 DNA 构象倾向对蛋白质结合的间接影响的定量结构功能相关性。