Folding/Unfolding Kinetics of Apomyoglobin

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• 作者：E. N. Baryshnikova ; B. S. Melnik ; G. V. Semisotnov and V. E. Bychkova
• 关键词：protein folding ; folding intermediates ; apomyoglobin ; folding rate
• 刊名：Molecular Biology
• 出版年：2005
• 出版时间：November 2005
• 年：2005
• 卷：39
• 期：6
• 页码：884-891
• 全文大小：135 KB

文摘

The equilibrium and kinetic folding/unfolding of apomyoglobin (ApoMb) were studied at pH 6.2, 11 ¡ãC by recording tryptophan fluorescence. The equilibrium unfolding of ApoMb in the presence of urea was shown to involve accumulation of an intermediate state, which had a higher fluorescence intensity as compared with the native and unfolded states. The folding proceeded through two kinetic phases, a rapid transition from the unfolded to the intermediate state and a slow transition from the intermediate to the native state. The accumulation of the kinetic intermediate state was observed in a wide range of urea concentrations. The intermediate was detected even in the region corresponding to the unfolding limb of the chevron plot. Urea concentration dependence was obtained for the observed folding/unfolding rate. The shape of the dependence was compared with that of two-state proteins characterized by a direct transition from the unfolded to the native state.