Conformational Analysis of Selectins

描述（由申请人提供）：选择素是介导白细胞和内皮细胞之间细胞-细胞接触的重要分子，通过与相对细胞上的碳水化合物配体结合。这些接触导致白细胞滚动，这是炎症反应的早期步骤。抑制这些相互作用提供了一种可能的方法来治疗许多疾病，包括关节炎，银屑病和转移。选择素在滚动过程中经历大的构象变化，从而改变其对碳水化合物的亲和力。 在这里，提出了P-选择素的高亲和力构象的晶体结构（由Uyen Phan在Springer实验室创建）将在有和没有结合配体的情况下得到解决。 平行地，L-选择素的结晶将是直接目标，因为没有L-选择素的结构，并且在选择素之间存在底物特异性差异。锁定在低亲和力构象的P-选择素将通过添加二硫键来构建，并在有或没有结合的碳水化合物的情况下结晶。将使用流动室测定来评估这种低亲和力构象与各种底物的结合。这项工作将深入了解滚动的机制，以及碳水化合物结合界面的重要结构特征，这可能是抑制剂的目标。

DESCRIPTION (provided by applicant): Selectins are important molecules in mediating cell-cell contacts between leukocytes and endothelial cells, by binding to carbohydrate ligands on opposing cells. These contacts lead to leukocyte rolling, an early step in the inflammatory response. Inhibiting these interactions provides a possible approach to treating a number of disorders including arthritis, psoriasis, and metastasis. The selectins undergo large conformational changes during the process of rolling that alter their affinity for carbohydrates. Here it is proposed that a crystal structure of the high affinity conformation of P-selectin (created by Uyen Phan in the Springer lab) will be solved with and without bound ligand. In parallel, crystallization of L-selectin will be an immediate goal, as there are no structures for L-selectin, and there are substrate specificity differences among the selectins. P-selectin locked in a low affinity conformation will be constructed by the addition of disulfide bonds, and crystallized, with and without bound carbohydrate. Flow chamber assays will be used to assess the binding of this low affinity conformation to various substrates. This work will give insight into the mechanism of rolling, and the important structural features of the carbohydrate binding interface, the likely target for inhibitors.