SAX ANALYSIS OF CHANGE: LIGAND BINDING TO GLUCOSE/GALACTOSE BINDING PROTEIN

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。列出的机构是 研究中心，而研究中心不一定是研究者所在的机构。 D-葡萄糖/D-半乳糖结合蛋白（GGBP）在许多细菌物种中介导葡萄糖和半乳糖的趋化性和主动转运。 GGBP与其他周质结合蛋白一样，可以开放（无配体，无活性）和封闭（配体结合，信号传导）状态存在。 利用我们实验室最近解决的GGBP的开放的、未结合的晶体结构，我们设计了一种小分子，其通过抑制葡萄糖趋化性并将蛋白质楔入开放构象来充当GGBP拮抗剂。 这是第一个（据我们所知）拮抗剂描述这个大而多样的家庭。 我们打算通过小角X射线散射（SAXS）实验进一步表征拮抗剂结合状态的GGBP。 我们建议进行SAXS实验上未绑定的GGBP，生产力绑定（葡萄糖/半乳糖绑定）GGBP和拮抗剂绑定的GGBP，以表征在溶液中发生的构象变化后，绑定。 这些实验的结果将帮助我们了解这种拮抗剂是如何工作的，并确定这种基于结构的设计方法是否可以被证明是抑制这种一般结构的受体的一般方法。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. D-Glucose/D-Galactose-binding protein (GGBP) mediates chemotaxis toward and active transport of glucose and galactose in a number of bacterial species. GGBP, like other periplasmic binding proteins, can exist in open (ligand-free, inactive) and closed (ligand-bound, signaling) states. Using an open, unbound crystal structure of GGBP recently solved by our lab, we have designed a small molecule that acts as a GGBP antagonist by inhibiting glucose chemotaxis and wedging the protein into an open conformation. This is the first (to our knowledge) antagonist described for this large and diverse family. We intend to further characterize the antagonist-bound state of GGBP via small angle X-ray scattering (SAXS) experiments. We propose to carry out SAXS experiments on unbound GGBP, productively-bound (glucose/galactose-bound) GGBP and antagonist-bound GGBP to characterize conformational changes that occur in solution upon binding. The results of these experiments will help us understand how this antagonist works and determine whether this structure-based design method could prove to be a general way to inhibit receptors of this general architecture.