REPEAT-PROTEINS; STABILITY, FOLDING KINETICS & EVOLUTION

重复-蛋白质；

• 批准号: 7193380
• 负责人: DOUGLAS E. BARRICK
• 金额: $ 22.65万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-03-01 至 2009-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7193380
• 关键词: Address; Adopted; Amino Acid Sequence; Architecture; Biological Process; Chimera organism; Computer Analysis; Coupling; DNA Sequence Rearrangement; Data; Disease; Equilibrium; Evolution; Facility Construction Funding Category; Family; Genes; Genetic; Genetic Recombination; Helix (Snails); Individual; Introns; Kinetics; Learning; Length; Life; Malignant Neoplasms; Maps; Measures; Methods; Modeling; Molecular Conformation; Numbers; Outcome; Pathogenesis; Pathway interactions; Peat; Peptide Sequence Determination; Play; Positioning Attribute; Protein Analysis; Protein Family; Protein Fragment; Proteins; Rate; Reaction; Research; Resolution; Role; Sequence Analysis; Series; Shapes; Signal Transduction; Solubility; Structure; System; Tandem Repeat Sequences; Testing; Time; Variant; base; ear helix; genome sequencing; insertion/deletion mutation; protein folding; protein protein interaction; research study; stem

DESCRIPTION (provided by applicant): In all branches of life, there are a variety of proteins that contain short, tandemly repeated sequences. Each repeat-sequence folds up into a closed loop containing helices, beta-strands, or a mix of secondary structure units. Adjacent repeats then pack against each other to create an elongated, linear domain with a regular, modular architecture. These repeat-proteins usually participate in protein-protein interactions, often at the center of important biological processes such as signal transduction, and are often associated with disease states such as cancer and bacterial pathogenesis. In the research outlined here, biophysical studies will be performed on repeat-proteins to better understand their folding and their stability. Our experiments will take advantage of the linear architecture of these proteins to answer questions that are difficult to address with non-repeat proteins. We will determine the distances over which repeats can couple with one another, and measure the end-to-end stability distribution in these proteins. We will use deletion experiments to build an "energy landscape" with single-repeat resolution. We will then examine how this "energy landscape" relates to folding rates by studying the folding kinetics of repeat-protein fragments and by determining which repeats are structured in the rate-limiting steps in folding, and will test models that relate folding rates to various structural and energetic features. Owing to their linear, repeated architecture, repeat-proteins seem likely targets for rapid evolution through insertion and deletion. We will evaluate the outcome of such rearrangements by studying the effects on stability of different types of deletions and duplications. We will test whether the fusion of different types of repeat-proteins can adopt a stable fold. The finding that such rearranged proteins are stable would support the idea that functional diversity can be produced by recombination of genes encoding repeat-proteins. We will also seek support for the hypothesis that repeat-proteins appeared early in protein evolution by computer analysis of protein sequences and structures.

描述（由申请人提供）：在生命的所有分支中，都有多种蛋白质包含短而串联重复的序列。每个重复序列都折叠成一个包含螺旋，β链或二级结构单元的混合物的封闭环。然后，相邻重复彼此相对应包装，以创建一个带有常规的模块化体系结构的拉长线性域。这些重复蛋白通常参与蛋白质 - 蛋白质相互作用，通常是信号转导的重要生物学过程的中心，通常与疾病状态（例如癌症和细菌发病机理）有关。在此处概述的研究中，将对重复蛋白进行生物物理研究，以更好地了解它们的折叠和稳定性。我们的实验将利用这些蛋白质的线性结构来回答难以解决非重复蛋白的问题。我们将确定重复可以彼此对夫妇的距离，并测量这些蛋白质中的端到端稳定性分布。我们将使用删除实验来建立具有单重分分辨率的“能量景观”。然后，我们将通过研究重复蛋白片段的折叠动力学，并确定哪些重复序列在折叠的速率限制步骤中结构，并测试将折叠速率与各种结构性和能量特征相关联的模型来研究这种“能量格局”如何与折叠率相关。由于它们的线性重复体系结构，重复蛋白似乎可能通过插入和删除来快速发展。我们将通过研究对不同类型缺失和重复的稳定性的影响来评估此类重排的结果。我们将测试不同类型的重复蛋白的融合是否可以采用稳定的折叠。这种重新排列的蛋白质稳定的发现将支持以下观点：通过编码重复蛋白的基因重组可以产生功能多样性。我们还将寻求支持假设，即通过计算机分析蛋白质序列和结构，重复蛋白在蛋白质演化早期出现。