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.

该建议具有与（a）确定的长期目标 胰岛素样生长因子I（IGF-I）的结构属性 确定其与I型IGF受体相互作用的效力及其 因此总体生物学作用，（b）评估的发展 可能适用于亲和力决定因素的规则和 在结构相关组中的受体相互作用的选择性 配体和受体，以及（c）考虑开发的潜力 可能具有治疗或实验价值的IGF-I类似物。 该项目的具体目标总结如下：（a）到 准备杂交IGF-I/胰岛素类似物，并具有选定的结构变化和 化学肽合成和半合成的氨基酸替代。 （b）评估这些类似物的效力 通过结合结合I型IGF和胰岛素受体的能力 竞争研究和直接分析放射性标记的配体结合。 （C） 考虑受体站点亲和力和选择性的单独问题 通过比较类似物，与IGF-I和胰岛素系统有关 与两个受体的相互作用。 （d）解决潜在方面 通过光谱方法的类似方法的溶液结构差异 和化学修饰。 （e）评估结构的后果 这些类似物在其生物学活动中的变化 体外，通过将3H-胸苷掺入DNA和用于DNA的测定法和 其他代谢反应。 （f）评估潜在的生物学 结合位点异质性与配体相互作用的含义 I型IGF受体通过相关结合的动力学分析 研究。 （g）了解I型IGF受体的理解 通过使用化学和亲和力，分子水平的异质性 方法。 由于可以预期IGF-I生理学的畸变会导致 在不同的情况下，在不适当的情况下或 组织生长速率不当，并且IGF-I系统可能 在胰岛素抵抗状态下通过胰岛素系统有用， 想象与健康相关的潜在重要性并不困难 IGF-i的类似物可能（a）对其一个或另一个的选择性 动作，（b）比天然激素更有效，（c）抑制 通过与受体结合而无需诱导细胞的作用内源激素 反应，或（d）通过多个受体系统起作用以产生所需的 代谢作用。 该建议代表了对IGF-I系统的研究 在此阶段的基本层面，以及 化学肽合成和半合成相关的 结构功能关系。