Becker J, Craig E A
Department of Biomolecular Chemistry, University of Wisconsin Medical School, Madison 53706.
Eur J Biochem. 1994 Jan 15;219(1-2):11-23. doi: 10.1007/978-3-642-79502-2_2.
Functional proteins within cells are normally present in their native, completely folded form. However, vital processes of protein biogenesis such as protein synthesis and translocation of proteins into intracellular compartments require the protein to exist temporarily in an unfolded or partially folded conformation. As a consequence, regions buried when a polypeptide is in its native conformation become exposed and interact with other proteins causing protein aggregation which is deleterious to the cell. To prevent aggregation as proteins become unfolded, heat-shock proteins protect these interactive surfaces by binding to them and facilitating the folding of unfolded or nascent polypeptides. In other instances the binding of heat-shock proteins to interactive surfaces of completely folded proteins is a crucial part of their regulation. As heat shock and other stress conditions cause cellular proteins to become partially unfolded, the ability of heat-shock proteins to protect cells against the adverse effects of stress becomes a logical extension of their normal function as molecular chaperones.
细胞内的功能蛋白通常以其天然的、完全折叠的形式存在。然而，蛋白质生物合成的重要过程，如蛋白质合成以及蛋白质转运到细胞内区室，需要蛋白质暂时以未折叠或部分折叠的构象存在。因此，当多肽处于其天然构象时被掩埋的区域会暴露出来，并与其他蛋白质相互作用，导致蛋白质聚集，这对细胞是有害的。为了防止蛋白质在展开时发生聚集，热休克蛋白通过与这些相互作用表面结合并促进未折叠或新生多肽的折叠来保护它们。在其他情况下，热休克蛋白与完全折叠的蛋白质的相互作用表面结合是其调节的关键部分。由于热休克和其他应激条件会导致细胞蛋白质部分展开，热休克蛋白保护细胞免受应激不利影响的能力成为其作为分子伴侣正常功能的合理延伸。
