SEQUENCE DEPENDENCE OF PROTEIN FOLDING KINETICS

蛋白质折叠需要天然状态的途径的存在。 虽然氨基酸残基对热力学的贡献 蛋白质的稳定性已被深入研究，但知之甚少 关于氨基酸序列如何指定折叠路径。 拟议 研究是结合分子生物学和生物物理学的方法， 这个问题 因为折叠问题的复杂性增加了 与链长，研究将集中在最短的一个 已知折叠成独特、稳定结构而无二硫键的序列 bonds：消化链球菌蛋白L的56个残基IgG结合结构域。 极重诱变蛋白L，随后选择IgG 使用噬菌体展示技术的结合将用于产生 采用相同折叠的非常不同的序列的数据库。 分析 数据库中保存的特征的分析应该识别残基， 在指定折叠途径中重要的相互作用。 测定 序列的发散子集的折叠时间将提供 深入了解序列如何控制遍历的选择和速率， 动力学途径 最慢折叠突变体的折叠途径 将使用核磁共振方法绘制地图。 序列、速率和结构 数据库连同生物物理数据的折叠途径将 用于指导和约束定量理论的发展， 这个小蛋白质的折叠。 详细了解氨基 在这个最简单的可能情况下，酸序列指定了三级结构 应该有助于理解更复杂的 proteins.

Protein folding requires the existence of pathways to the native state. Although the contribution of amino acid residues to the thermodynamic stability of proteins has been intensively studied, very little is known about how amino acid sequences specify folding pathways. The proposed research is a combined molecular biological and biophysical approach to this problem. Because the complexity of the folding problem increases with chain length, the research will focus on one of the shortest sequences known to fold into a unique, stable structure without disulfide bonds: the 56 residue IgG binding domain of Peptostreptococcal Protein L. Extremely heavy mutagenesis protein L followed by selection for IgG binding using the phage display technology will be used to generate a database of very divergent sequences which adopt the same fold. Analysis of features conserved in the database should identify residues and interactions important in specifying the folding pathway. Determination of the folding times of a divergent subset of the sequences will provide insight into how sequence controls the selection and rate of traversal of kinetic pathways. The folding pathways of the most slowly folding mutants will be mapped using NMR methods. The sequence, rate and structure database together with the biophysical data on the folding pathway will be used to guide and constrain the development of a quantitative theory for the folding of this small protein. A detailed understanding of how amino acid sequence specifies tertiary structure in this simplest possible case should contribute to the understanding of the folding of more complex proteins.