Kiefhaber T
Abteilung Biophysikalische Chemie, Universität Basel, Switzerland.
Proc Natl Acad Sci U S A. 1995 Sep 26;92(20):9029-33. doi: 10.1073/pnas.92.20.9029.
Folding of lysozyme from hen egg white was investigated by using interrupted refolding experiments. This method makes use of a high energy barrier between the native state and transient folding intermediates, and, in contrast to conventional optical techniques, it enables one to specifically monitor the amount of native molecules during protein folding. The results show that under strongly native conditions lysozyme can refold on parallel pathways. The major part of the lysozyme molecules (86%) refold on a slow kinetic pathway with well-populated partially folded states. Additionally, 14% of the molecules fold faster. The rate constant of formation of native molecules on the fast pathway corresponds well to the rate constant expected for folding to occur by a two-state process without any detectable intermediates. The results suggest that formation of the native state for the major fraction of lysozyme molecules is retarded compared with the direct folding process. Partially structured intermediates that transiently populate seem to be kinetically trapped in a conformation that can only slowly reach the native structure.
通过使用中断复性实验研究了鸡蛋清溶菌酶的折叠过程。该方法利用了天然状态与瞬时折叠中间体之间的高能垒，并且与传统光学技术不同，它能够在蛋白质折叠过程中特异性地监测天然分子的数量。结果表明，在强天然条件下，溶菌酶可以通过平行途径复性。大部分溶菌酶分子（86%）通过一条具有大量部分折叠状态的缓慢动力学途径复性。此外，14%的分子折叠得更快。快速途径上天然分子形成的速率常数与通过无任何可检测中间体的两态过程发生折叠所预期的速率常数非常吻合。结果表明，与直接折叠过程相比，大部分溶菌酶分子天然状态的形成受到了阻碍。短暂存在的部分结构化中间体似乎在动力学上被困在一种只能缓慢达到天然结构的构象中。
