Wenzel T, Baumeister W
Max-Planck-Institut für Biochemie, Martinsried, Germany.
FEBS Lett. 1993 Jul 12;326(1-3):215-8. doi: 10.1016/0014-5793(93)81793-y.
It is shown that proteasomes from the arachaebacterium Thermoplasma acidophilum selectively degrade substrate proteins partially unfolded by phenylhydrazine- or hydrogen peroxide-treatment. Surprisingly, the pre-incubation of the substrate proteins with ubiquitin is also sufficient to render them susceptible to proteolytic degradation by proteasomes. We propose that, upon spontaneously associating with the substrate protein, ubiquitin exerts a chaotropic effect on it; this may involve the exposure of hydrophobic segments of the polypeptide chain which are recognized by the binding sites of the proteasome.
结果表明，嗜热栖热放线菌的蛋白酶体可选择性降解经苯肼或过氧化氢处理而部分展开的底物蛋白。令人惊讶的是，底物蛋白与泛素预孵育也足以使其易于被蛋白酶体进行蛋白水解降解。我们提出，泛素在与底物蛋白自发结合时，会对其产生离液效应；这可能涉及多肽链疏水片段的暴露，而这些片段可被蛋白酶体的结合位点识别。
