Direct single-molecule observation of a protein living in two opposed native structures
Direct single-molecule observation of a protein living in two opposed native structures
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DOI：
10.1073/pnas.0904461106
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发表时间：
2009-06-23
影响因子：
11.1
通讯作者：
Deniz, Ashok A.
中科院分区：
文献类型：
--
作者：
Gambin, Yann;Schug, Alexander;Deniz, Ashok A.
蛋白质的生物活性要求它们共享折叠和全局构象运动的能量景观，这是功能的两个关键决定因素。虽然迄今为止大多数结构研究都集中在一个单一的结构盆地周围的波动，我们直接观察到的Rop同源二聚体（引物抑制剂）的突变体的2对称相反的构象共存的单分子荧光共振能量转移（smFRET）测量。我们发现，温和的变性条件可以影响构象之间的敏感的平衡，产生一个平衡的合奏组成的2个同样占据的结构盆地。尽管需要大规模的构象重排，这两种天然结构的动态和可逆地采用相同的配对分子，而不分离的组成单体。一些蛋白质或蛋白质复合物通过热波动和/或微小的环境变化在构象之间切换的这种能力可能是它们控制生物功能的能力的核心。
Biological activity in proteins requires them to share the energy landscape for folding and global conformational motions, 2 key determinants of function. Although most structural studies to date have focused on fluctuations around a single structural basin, we directly observe the coexistence of 2 symmetrically opposed conformations for a mutant of the Rop-homodimer ( Repressor of Primer) in single-molecule fluorescence resonance energy transfer (smFRET) measurements. We find that mild denaturing conditions can affect the sensitive balance between the conformations, generating an equilibrium ensemble consisting of 2 equally occupied structural basins. Despite the need for large-scale conformational rearrangement, both native structures are dynamically and reversibly adopted for the same paired molecules without separation of the constituent monomers. Such an ability of some proteins or protein complexes to switch between conformations by thermal fluctuations and/or minor environmental changes could be central to their ability to control biological function.