The folding energy landscape of apoflavodoxin is rugged: Hydrogen exchange reveals nonproductive misfolded intermediates
The folding energy landscape of apoflavodoxin is rugged: Hydrogen exchange reveals nonproductive misfolded intermediates
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DOI：
10.1073/pnas.0509133103
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发表时间：
2006-03-14
影响因子：
11.1
通讯作者：
van Mierlo, CPM
中科院分区：
文献类型：
--
作者：
Bollen, YJM;Kamphuis, MB;van Mierlo, CPM
许多天然蛋白质偶尔会形成部分未折叠形式(PUF)，这可以通过氢/氢交换和核磁共振光谱来检测。为了更好地理解折叠相关疾病的发病，需要了解这些亚稳态的知识。到目前为止，人们还不太清楚PUF在蛋白质折叠的能量版图中处于什么位置。在这里，鉴定了四个相对较大的载黄素(179氨基酸)的PUF。值得注意的是，其中至少有三个是部分错误折叠的构象。错误折叠涉及到侧链接触以及蛋白质骨架。PUF与天然蛋白质相互转化的速率已经确定。将这些速率与停流数据进行比较，可以将PUF定位在载黄素复杂的折叠能量图景中。PUF1和PUF2是从天然脱脂黄毒素开始但不继续到未折叠状态的展开短途旅行。PUF3和PUF4可能是类似的漂移，但它们的形成速度表明它们处于死胡同的折叠路线上，从未折叠的载黄素开始，而不是一直持续到天然蛋白质。因此，所有检测到的PUF都离开了蛋白质的高效折叠路线。
Many native proteins occasionally form partially unfolded forms (PUFs), which can be detected by hydrogen/deuterium exchange and NMR spectroscopy. Knowledge about these metastable states is required to better understand the onset of folding-related diseases. So far, not much is known about where PUFs reside within the energy landscape for protein folding. Here, four PUFs of the relatively large apoflavodoxin (179 aa) are identified. Remarkably, at least three of them are partially misfolded conformations. The misfolding involves side-chain contacts as well as the protein backbone. The rates at which the PUFs interconvert with native protein have been determined. Comparison of these rates with stopped-flow data positions the PUFs in apoflavodoxin's complex folding energy landscape. PUF1 and PUF2 are unfolding excursions that start from native apoflavodoxin but do not continue to the unfolded state. PUF3 and PUF4 could be similar excursions, but their rates of formation suggest that they are on a dead-end folding route that starts from unfolded apoflavodoxin and does not continue all of the way to native protein. All PUFs detected thus are off the protein's productive folding route.