Activities of nucleoprotein complexes visualized in single-molecule experiments

描述(申请人提供)：对生物的机械理解要求我们理解蛋白质和DNA如何相互作用来产生功能染色体。这一理解对于保护人类健康、处理遗传疾病和抗击病原体至关重要。拟议的项目侧重于单分子分析，允许直接可视化生物分子相互作用，并可用于详细分析蛋白质-DNA相互作用。该提案的目的包括仔细研究从DNA中去除蛋白质的“交换”机制，该机制建议对DNA上蛋白质周转的传统描述进行重大修订，并将影响对基因调节和染色体结构蛋白质的广泛研究。第二个目标是直接研究大的“染色体结构维持”蛋白质复合体的机制，这种复合体在真核细胞中介导染色体的折叠。最后，第三个目标集中在一系列“剪切和粘贴”DNA重组系统的潜在机制上，这些系统在一定程度上负责产生细菌的遗传多样性。对DNA加工机制的高度机械化分析将使我们更好地理解细胞如何解释、折叠和改变其基因组，从而更好地理解这些功能受损的病理学，以及更好地理解如何针对病原体中的这些功能。

DESCRIPTION (provided by applicant): Mechanistic understanding of living things requires our understanding of how proteins and DNA interact together to generate functional chromosomes. This understanding is central to preserving human health, dealing with genetic disorders, and fighting pathogenic organisms. The proposed projects are focused on single-molecule analyses which permit direct visualization of biomolecule interactions, and can be used to analyze protein-DNA interactions in detail. The aims of the proposal include careful study of an "exchange" mechanism for removal of proteins from DNA that suggests a major revision of conventional descriptions of protein turnover on DNA, and which will affect a wide range of studies of gene regulatory and chromosome-structural proteins. A second aim is focused on direct study of mechanisms of large "Structural Maintenance of chromosomes" protein complexes which mediate the folding of chromosomes in eukaryote cells. Finally, a third aim is focused on mechanisms underlying a family of "cut and paste" DNA recombination systems responsible in part for generating bacteria genetic diversity. The highly mechanistic analyses of DNA-processing machinery that are proposed will give us a stronger understanding of how cells interpret, fold and change their genomes, leading to a better understanding of pathologies where those functions are impaired, and better understanding of how to target those functions in pathogenic organisms.