The Encounter Complex in Antibody-Antigen Reactions

抗体-抗原反应中的相遇复合体

• 批准号: 9807950
• 负责人: Jefferson Foote
• 金额: $ 30万
• 依托单位: Fred Hutchinson Cancer Research Center
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-09-01 至 2001-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9807950&HistoricalAwards=false
• 关键词: Encounter; Complex; Antibody; Antigen; Reactions

9807950FooteMolecular recognition between biological macromolecules is thought often to occur through a transient intermediate known as an "encounter complex". In this complex, two reactants come into proximity and collide repeatedly. They do not necessarily form bonds with each other, but cannot easily escape because they are packed against each other by solvent. The investigator's long term goal is to develop experimental approaches to study encounter complexes. The investigator proposes a method for resolving encounter complex formation into component steps, and will apply this method to antibody recognition of antigens. The method is to construct monovalent and divalent versions of the same antibody and measure the kinetics of antigen binding by each. Loss of one binding site creates a deficit in reaction rate that affects the specific interaction with antigen, but not the general processes of diffusion and non-specific collisions. This theory will be tested with mutant antibodies and antigens, using primarily stopped-flow fluorescence to measure kinetics. The model system employed will be the antigen lysozyme and a humanized version of an anti-lysozyme antibody. These studies will elucidate new principles of ligand-receptor interaction that underlie the reactivity of antibodies and other molecules of the immune system. The investigator proposes a new way of analyzing chemical reactions between complex biological molecules such as proteins. Macromolecules in water move about uneventfully for a long time, then undergo a rapid series of collisions when they meet each other. Two molecules engaged in this collision process are called an "encounter complex". Computer calculations indicate that the encounter complex is an important intermediate in crucial life processes, such as the recognition of foreign materials by antibodies. The investigator plans to test this theory experimentally, and to develop a general method of looking at the biological role of the encounter complex.

9807950Foote生物大分子之间的分子识别通常被认为是通过称为“相遇复合物”的瞬时中间体发生的。 在这个复合物中，两种反应物不断靠近并碰撞。它们不一定彼此形成键，但不能轻易逃脱，因为它们通过溶剂相互堆积。研究人员的长期目标是开发研究遭遇情结的实验方法。研究人员提出了一种将相遇复合物形成分解为多个步骤的方法，并将将该方法应用于抗原的抗体识别。 该方法是构建同一抗体的单价和二价版本，并测量每种抗体结合抗原的动力学。失去一个结合位点会导致反应速率下降，从而影响与抗原的特异性相互作用，但不会影响扩散和非特异性碰撞的一般过程。该理论将通过突变抗体和抗原进行测试，主要使用停流荧光来测量动力学。所采用的模型系统将是抗原溶菌酶和抗溶菌酶抗体的人源化版本。 这些研究将阐明配体-受体相互作用的新原理，该原理是抗体和免疫系统其他分子反应性的基础。 研究人员提出了一种分析蛋白质等复杂生物分子之间化学反应的新方法。水中的大分子会长时间平稳地运动，然后当它们彼此相遇时会发生一系列快速的碰撞。参与此碰撞过程的两个分子称为“相遇复合体”。计算机计算表明，遭遇复合体是关键生命过程中的重要中间体，例如抗体识别外来物质。研究人员计划通过实验检验这一理论，并开发一种通用方法来研究遭遇复合体的生物学作用。