SEMISYNTHETIC IGF-I/INSULIN HYBRIDS AS RECEPTOR PROBES

半合成 IGF-I/胰岛素杂交体作为受体探针

• 批准号: 2143174
• 负责人: DONALD F STEINER
• 金额: $ 19.74万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-02-01 至 1997-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2143174
• 关键词: affinity labeling; chimeric proteins; fibroblasts; human tissue; insulin; insulin receptor; insulinlike growth factor; peptide chemical synthesis; peptide hormone analog; protein structure function; radiotracer; receptor binding; tissue /cell culture

This proposal has long-term goals related to (a) identifying the structural attributes of insulin-like growth factor I (IGF-I) which determine its potency for interactions with type I IGF receptors, and its consequent overall biological effects, (b) evaluating the development of rules that might apply to the separate determinants of affinity and selectivity for receptor interactions within structurally related groups of ligands and receptors, and (c) considering the potential for development of IGF-I analogs that might be of therapeutic or experimental value. Specific aims for the project are summarized as follows: (a) To prepare hybrid IGF-I/insulin analogs with selected structural changes and amino acid replacements by chemical peptide synthesis and semisynthesis. (b) To evaluate the potencies of these analogs with regard to their abilities to bind to the type I IGF and insulin receptors through binding competition studies and direct analysis of radiolabeled ligand binding. (c) To consider the separate issues of receptor site affinity and selectivity in relation to the IGF-I and insulin systems through comparisons of analog interactions with both receptors. (d) To address aspects of potential differences in the solution structures of analogs by spectroscopic methods and chemical modification. (e) To evaluate the consequences of structural changes in these analogs in relation to their biological activities in vitro, by use of assays for 3H-thymidine incorporation into DNA and for additional metabolic responses. (f) To evaluate the potential biological implications of binding site heterogeneity in ligand interactions with the type I IGF receptor through the kinetic analysis of related binding studies. (g) To approach an understanding of type I IGF receptor heterogeneity at the molecular level through use of chemical and affinity methods. As aberrations in IGF-I physiology can be expected to result under different sets of circumstances in either inappropriately low or inappropriately high rates of tissue growth, and as the IGF-I system could be useful in by-passing the insulin system in states of insulin resistance, it is not difficult to envision the potential health-related importance of analogs of IGF-I that might (a) be selective for one or the other of its actions, (b) be even more potent than the natural hormone, (c) inhibit the action endogenous hormone by binding to receptor without inducing cellular responses, or (d) act through multiple receptor systems to produce desired metabolic effects. This proposal represents a study of the IGF-I system at a fundamental level, at this stage, and the application of the methods of chemical peptide synthesis and semisynthesis to the elucidation of relevant structure-function relationships.

该提案有长期目标，涉及(A)确定 胰岛素样生长因子-I的结构属性 确定其与I型IGF受体相互作用的效力，以及其 由此产生的总体生物影响，(B)评价 可能适用于亲和力和亲和力的不同决定因素的规则 结构相关基团中受体相互作用的选择性 配体和受体，以及(C)考虑到发展的潜力 IGF-I类似物，可能具有治疗或实验价值。 该项目的具体目标概述如下：(A) 制备具有特定结构变化的IGF-I/胰岛素杂化类似物 氨基酸的化学合成和半合成替代。 (B)评估这些类似物相对于其 通过结合与I型IGF和胰岛素受体结合的能力 放射性标记配体结合的竞争研究和直接分析。(C) 考虑受体位置亲和力和选择性的不同问题 与胰岛素样生长因子-I和胰岛素系统的关系 与两种受体的相互作用。(D)处理潜在问题的各个方面 用光谱方法研究类似物溶液结构的差异 和化学修饰。(E)评估结构性改革的后果 这些类似物的变化与其生物学活性有关 在体外，通过~3H-胸腺嘧啶核苷掺入DNA和 额外的代谢反应。(F)评估潜在的生物 配基相互作用中结合部位异质性的意义 I型胰岛素样生长因子受体相关结合的动力学分析 学习。(G)探讨对I型IGF受体的理解 通过使用化学和亲和力在分子水平上的异质性 方法：研究方法。 因为IGF-I生理学中的像差可以预期会导致 在不同的情况下，在不适当的低或 过高的组织生长率，以及IGF-I系统可能 在胰岛素抵抗状态下绕过胰岛素系统是有用的， 不难想象，与健康相关的潜在重要性 IGF-I的类似物，可能(A)对其一个或另一个具有选择性 作用，(B)比天然荷尔蒙更有效，(C)抑制 内源性激素通过与受体结合而不诱导细胞 反应，或(D)通过多个受体系统作用，以产生所需的 新陈代谢影响。本提案代表对IGF-I系统的研究，网址为 一个基本的层面，在这个阶段，和方法的应用 化学肽的合成和半合成对相关物质的阐明 结构-功能关系。