FOLDING OF GROUP II INTRON RIBOZYME

在蛋白质中，同步加速器辐射分解的程度取决于 活性残留物的溶剂可及性。因为溶剂 离散残基的可及性将在相互作用时改变 HA蛋白与配基的同步辐射提供了一种方法 探测这些变化，并结合质谱学 分析、鉴定参与配基结合的氨基酸残基。 羟基自由基对蛋白质修饰的透明质酸变化 Hvs.蛋白质-配体复合体代表了一种足迹 Hfor残基与结合部位相互作用。我们已经选择了 人血小板膜蛋白(HPP)与HPP相互作用的研究 以多聚L-脯氨酸为模型蛋白质-配体络合物，作为其晶体 结构已经阐明了HPP中特定的氨基酸残基 结合多聚L-脯氨酸和羟丙氨酸的结构没有改变 基本上是通过该配体的结合。多聚L-脯氨酸 解离结果表明，多肽与HPP有很强的相互作用 复合体的常量。N-末端的Trp3和Tyr6残基 HPP的Lys-C多肽和Trp31一样参与结合。这个 毫秒X射线后残留的未修饰蛋白质的一部分 曝光量由质谱仪确定，并显示为函数 Hof时间和包含Lys-C的数据 蛋白质降解后的H结合残基。将这些数据与数据进行比较 从蛋白质-配基复合体的氢解来检查变化 蛋白质掺入的Htime分辨修饰 希根。

In proteins, the extent of synchrotron radiolysis is dependent on the solvent accessibility of the reactive residues. Since the solvent accessibility of discrete residues will be altered upon interaction of Ha protein with ligand, synchrotron radiolysis provides a method to probe these changes and, in combination with mass spectrometric analysis, identify the amino acid residues involved in ligand binding. HA change in the hydroxyl radical induced modification of the protein Hversus the protein-ligand complex is representative of a footprint Hfor residues that interact at the binding site. We have chosen to Hstudy the interaction between human platelet profilin (HPP) and Hpoly-L-proline as a model protein-ligand complex, as its crystal structure has elucidated the specific amino acid residues in HPP that bind poly-L-proline and that the structure of HPP is not altered substantially by the binding of this ligand. The poly-L-proline peptide interacts strongly with HPP as indicated by the dissociation constants for the complex . Residues Trp3 and Tyr6 in the N-terminal Lys-C peptide of HPP participate in binding as does Trp31. The fraction of unmodified protein that remains after millisecond x-ray exposure is determined by mass spectrometry and is shown as a function Hof time together with data for the Lys-C peptides that contain the Hbinding residues after proteolysis. These are compared with data from Hradiolysis of the protein-ligand complex to examine changes to the Htime-resolved modification of protein with the incorporation of Hligand.