ROLE OF HEAT SHOCK PROTEINS IN PROTEIN FOLDING

哺乳动物(和其他)细胞通过增加一种蛋白的表达来应对压力 一类称为热休克蛋白的蛋白质。这些蛋白质中的大多数是 在正常条件下产生，并在 细胞的寿命。最近的研究表明，哺乳动物的热休克蛋白70 热休克蛋白家族及其相关多肽链结合 来自其他来源的蛋白质和分子伴侣(例如GroEL)可以结合 到短肽，到细胞中的新生多肽，并参与 在蛋白质组装、转位和折叠的各个方面。这个 相对较大比例的细胞蛋白质，尤指在 应激，以这种蛋白质的形式存在，以及 突变形式，表明它们对细胞功能至关重要。连 虽然蛋白质在体外可以自发折叠，但事实并非如此。 很明显，这就是活体内的情况。事实上，一个很好的理由是 在电池中折叠和组装时需要某种形式的辅助 以最大限度地减少竞争副反应。建议的目标是 研究是为了确定HSP70及其相关分子的细节 多肽链结合蛋白促进蛋白质的折叠和组装 底物蛋白质。热休克蛋白70蛋白的生物物理特性 将提供有关其结构和稳定性的信息。的一大部分 这项提议涉及到阐明该病毒的分子细节。 热休克蛋白70与底物蛋白的相互作用及三磷酸腺苷的作用 在这个过程中。这些研究将在体外条件下进行。 条件。相互作用的化学计量和结合常数 将会被确定。从小单体到大分子的一系列蛋白质 寡聚体将被用作底物蛋白。热休克蛋白70对血管内皮细胞生长的影响 蛋白质折叠动力学及热休克蛋白70与中间体的亲和力 在折叠中将会被决定。结构和序列的特异性 将确定热休克蛋白70与蛋白质结合的要求。从… 我们希望这些研究能够提供详细的分子 对这类重要的细胞因子的功能的描述。

Mammalian (and other) cells respond to stress by increasing expression of a class of proteins known as heat shock proteins. Most of these proteins are produced constitutively under normal conditions and play essential roles in the life of the cell. Recent studies have shown that the mammalian hsp 70 family of heatshock proteins, and related polypeptide chain binding proteins and molecular chaperones (e.g. GroEL) from other sources, can bind to short peptides, and to nascent polypeptides in cells, and are involved in various aspects of protein assembly, translocation and folding. The relatively large fraction of cell protein, especially under conditions of stress, present as this type of protein, and the potential lethality of mutant forms, indicates their critical importance to cell function. Even though it is clear that proteins fold spontaneously in vitro, it is not clear that this is the case in vivo. In fact, a good case can be made for the need for some form of assistance in folding and assembly in the cell in order to minimize competing side reactions. The goal of the proposed research is to determine the molecular details of how hsp 70 and related polypeptide chain binding proteins facilitate the folding and assembly of substrate proteins. Biophysical characterization of the hsp 70 proteins will provide information on their structure and stability. A major part of the proposal concerns elucidation of the molecular details of the interaction of the hsp 70 with its substrate protein, and the role of ATP in this process. These studies will be carried out under in vitro conditions. The stoichiometry and binding constants for the interactions will be determined. A range of proteins from small monomeric to large oligomeric will be used as substrate proteins. The effect of hsp 70 on the kinetics of protein folding, and the affinity of hsp 70 for intermediates in folding will be determined. The structural and sequence specificity requirements for hsp 70 binding to proteins will be ascertained. From these investigations we expect to be able to provide a detailed molecular description of the function of this important class of cellular agent.