Structure and Function of Proline Permease

细胞生长的一个重要方面——必要的营养物质如何进入细胞（运输）——就其实际的分子运输机制和负责运输的蛋白质而言，人们知之甚少。沙门氏菌脯氨酸转运突变体将用于研究钠驱动转运的分子机制。通过选择特定类别的突变体，将确定参与底物结合和易位的蛋白酶结构域；借助相关残基的位点定向诱变，可以测试某些氨基酸的预测作用，并借助生物化学和生物物理方法来理解底物易位所需的构象变化。离子驱动转运蛋白的结构-功能关系的阐明应该从这些检查中得出。

An important aspect of cell growth--how necessary nutrients get into the cell (transport)--is poorly understood in terms of ther actual molecular mechanisms of transport and the proteins responsible for it. The proline transport mutants of Salmonella will be used for studies of the molecular mechanism of sodium- driven transport. By selection for particular classes of mutants, domains of the protease involved in substrate binding and translocation will be identified; with the aid of site directed mutagenesis of the implicated residues it whould be possible to test the predicted roles of certain amino acids and come to understand, with the aid of biochemical and biophysical approaches, the conformational changes necessary for substrate translocation. Elucidation of the structure-function relationships of ion-driven transport proteins should result from such examinations.