MULTIDENTATE HIGH AFFINITY LIGANDS FOR AB5 TOXINS

该提案的目标是利用多聚体蛋白质的结构对称性，这是一种很少探索的性质，最终获得具有超高亲和力和特异性的结构互补的多齿蛋白质配体。 长期目标是阐明一个基本的生物学兴趣领域：多齿蛋白质配体的分子识别特性和使用这种配体来控制蛋白质功能。具体而言，该建议包括设计，合成和评价的多齿配体靶向一对理想的模型系统：热不稳定肠毒素从大肠杆菌。大肠杆菌（LT）和密切相关的霍乱弧菌（CT）分泌的霍乱毒素，它们都是AB 5异六聚体。 LT和CT作用的生物学机制包括通过B五聚体识别靶细胞上的受体的关键步骤。 LT和CT的B亚基的五重对称性为开发具有与毒素受体结合位点的排列互补的总体结构的五齿配体提供了良好的机会。这样的配体将逐步创建使用模块化的方法与每个模块提供进一步优化的机会的分子识别的原则的基础上，我们提出的工作将结合联合收割机的组合化学和基于结构的设计的权力，以达到双亲和性五齿配体。 将用各种分析工具研究所获得的配体的亲和力。 详细的配体-蛋白质相互作用的热力学将使用一系列的单到五齿配体进行研究。拟议的研究具有广泛的影响，一般的分子识别领域，因为它是在调查的前沿，重点是多齿配体与多聚体蛋白质相互作用。 此外，从我们的工作中获得的高亲和力配体具有潜在的健康益处，因为它们可能导致用于检测、治疗和预防AB 5毒素相关的肠易激疾病的试剂的开发。

The goal of this proposal is to take advantage of the structural symmetry of multimeric proteins, a rarely explored property, to arrive eventually at structurally complementary multidentate protein ligands with ultra-high affinity and specificity. The long term objective is to illuminate an area of fundamental biological interest: the molecular recognition properties of multidentate protein ligands and the use of such ligands to control protein functions. Specifically, this proposal encompasses the design, synthesis and evaluation of multidentate ligands targeting a pair of ideal model systems: the heat-labile enterotoxin from E. coli (LT) and the closely related cholera toxin secreted by V. cholerae (CT), which are both AB5 heterohexamers. The biological mechanism of the actions of LT and CT includes a critical step of receptor recognition on the target cell by the B pentamer. The five-fold symmetry of the B subunits of LT and CT offers good opportunities to develop pentadentate ligands with overall structures complementary to the arrangement of toxin receptor binding sites. Such ligands will be created stepwise using a modular approach with each module providing opportunities for further optimization Building on the principles of molecular recognition, our proposed work will combine the powers of combinatorial chemistry and structure-based design to arrive at ultrahigh affinity pentadentate ligands. The affinity of the ligands obtained will be investigated with a variety of analytical tools. Detailed thermodynamics of ligand-protein interaction will be studied using a series of mono- to penta-dentate ligands. The proposed research has broad implications for the field of molecular recognition in general since it is at the frontiers of investigations focusing on multidentate ligands interacting with multimeric proteins. In addition, high affinity ligands derived from our work have potential health benefits, as they may lead to the development of agents useful for the detection, treatment, and prevention of AB5 toxin-related enterotoxigenic diseases.