SOLUTE TRANSPORT TAXIS AND SENSORY PATHWAY RECEPTORS

描述：许多结合蛋白(或 受体)有待确定。然而，X射线结晶学是 将采用的初步实验方法，生化，重组 DNA和计算技术也将被使用。这些蛋白质- 对各种碳水化合物、含氧酸(硫酸盐和 磷酸盐)、氨基酸、二肽和寡肽--作为初始 ATP驱动的转运系统或通透性的高亲和力受体 细菌。这组渗透率是三磷酸腺苷超家族的成员。 结合转运体不仅存在于原核生物中，也存在于真核生物中 (例如，哺乳动物P-糖蛋白多药耐药基因产物和 囊性纤维化跨膜电导调节剂)。其中三个 结合蛋白也是简单的 趋化性的行为反应。 建议改进选定的配位形式的结构 结合蛋白(例如，具有磷酸盐、硫酸盐、 阿拉伯糖、麦芽糖结合蛋白、亮氨酸/异亮氨酸/缬氨酸)接近1 A 使用SHELXL进行解析。 多种多样的溶质或营养物质 受体和广谱中的特异度最大 严格的(如磷酸盐)对最松散的(寡肽)是一个 有机会详细研究分子识别。特别的 利息是静电和疏水性的相对贡献 互动。要探索计算技术来评估它们的 关于这些相互作用对 受体家族中的特定分子识别范例(磷酸盐 与硫酸盐、单糖与寡糖、多肽与氨基酸等)。 受体提供了一个深入研究结构的绝佳机会。 大小约为25-60 kDa的蛋白质家族的特征 有很小的序列同源性，但可能会折叠成类似的 整体立体结构。

DESCRIPTION: The structure and function of a number of binding proteins (or receptors) are to be determined. Whereas, X-ray crystallography is the primary experimental approach which will be used, biochemical, recombinant DNA and computational techniques will also be employed. These proteins - with specificity for a variety of carbohydrates, oxyacids (sulfate and phosphate), amino acids, dipeptides and oligopeptides - serve as initial high affinity receptors of ATP-driven transport systems or permeases in bacteria. This group of permeases is a member of a superfamily of ATP binding transporters found not only in prokaryotes but also in eukaryotes (e.g. the mammalian P-glycoprotein multi-drug resistance gene product and the cystic fibrosis transmembrane conductance regulator). Three of the binding proteins also serve as primary chemoreceptors in the simple behavioral response of chemotaxis. It is proposed to refine the structures of the liganded forms of selected binding proteins (e.g. those with specificity of phosphate, sulfate, arabinose, maltose-binding protein, leucine/isoleucine/valine) close to 1 A resolution using SHELXL. The wide variety of solutes or nutrients recognized by the family of receptors and the wide spectrum in the degree of specificity from the most stringent (e.g. phosphate) to the most loose (oligopeptides) is an opportunity for detailed study of molecular recognition. Of particular interest are the relative contributions of electrostatic and hydrophobic interactions. Computational techniques are to be explored to evaluate their predictive value as to the relative contribution of these interactions to specific molecular recognition paradigms in the receptor family (phosphate vs. sulfate, mono- vs. oligosaccharides, peptides vs. amino acids, etc.). The receptors offer an excellent opportunity to delve into structural features of a family of proteins which range in size from about 25 to 60 kDa and share little sequence homology, yet presumably fold into a similar overall three-dimensional structure.