Fast and slow tracks in lysozyme folding: Insight into the role of domains in the folding process

被引:78
作者
Matagne, A [1 ]
Radford, SE [1 ]
Dobson, CM [1 ]
机构
[1] UNIV OXFORD,OXFORD CTR MOL SCI,NEW CHEM LAB,OXFORD OX1 3QT,ENGLAND
基金
英国工程与自然科学研究理事会; 英国生物技术与生命科学研究理事会;
关键词
protein folding; hen egg white lysozyme; multiple pathways; folding intermediates; stopped-flow fluorescence;
D O I
10.1006/jmbi.1997.0963
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
The folding of lysozyme involves parallel events in which hydrogen exchange kinetics indicate the development of persistent structure at very different rates. We have monitored directly the kinetics of formation of the native molecule by the binding of a fluorescently labelled inhibitor, MeU-diNAG (4-methylumbelliferyl-N,N'-diacetyl-beta-D-chitobioside). The data show that native character monitored in this way also develops with different timescales. Although the rate determining step on the slow pathway (similar to 75% of molecules at pH 5.5, 20 degrees C) can be attributed to the need to reorganise structure formed early in the folding process, the data indicate that the rate determining step on the fast track (involving similar to 25% of molecules) involves the docking of the two constituent domains of the protein. In the fast folding track the data are consistent with a model in which each domain forms persistent structure prier to their docking in a locally cooperative manner on a timescale comparable to the folding of small single domain proteins. (C) 1997 Academic Press Limited.
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页码:1068 / 1074
页数:7
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