Single-molecule fluorescence reveals sequence-specific misfolding in multidomain proteins.
Single-molecule fluorescence reveals sequence-specific misfolding in multidomain proteins.
复制标题
DOI：
10.1038/nature10099
复制
发表时间：
2011-05-29
期刊：
影响因子：
64.8
通讯作者：
Clarke, Jane
中科院分区：
文献类型：
--
作者：
Borgia, Madeleine B.;Borgia, Alessandro;Best, Robert B.;Steward, Annette;Nettels, Daniel;Wunderlich, Bengt;Schuler, Benjamin;Clarke, Jane
大量使人衰弱的疾病与蛋白质错误折叠有关，这可能与有效折叠相竞争，特别是在含有多个结构域的蛋白质中。真核生物蛋白质组中有75%是由多结构域蛋白组成的，如何避免结构域间的错误折叠？在共价连接结构域之间保持低序列同一性是避免错误折叠的一种机制。在这里，我们使用单分子Förster共振能量转移（FRET）实验来检测和量化天然条件下titin i波段串联Ig结构域的罕见错误折叠事件。约5.5%具有相同结构域的分子在体外重折叠过程中发生错误折叠，并形成令人惊讶的稳定状态，其展开一半时间为几天。人类免疫球蛋白样结构域串联序列在相邻结构域之间的序列同一性明显低于非相邻结构域之间的序列同一性。特别是相邻结构域的序列同一性优先低于40%。有趣的是，我们观察到低序列同一性的自然相邻结构域串联没有错误折叠（24%），而42%相同的结构域之间发生错误折叠。粗粒度的分子模拟预测了畴交换结构的形成，这与观察到的错误折叠物种的转移效率非常一致。我们推断，错误折叠背后的相互作用是非常特定的，并导致序列特定的区域交换机制。使相邻结构域之间的序列多样化似乎是避免多结构域蛋白错误折叠的一种成功的进化策略。
A large range of debilitating medical conditions are linked to protein misfolding, which may compete with productive folding particularly in proteins containing multiple domains. With 75% of the eukaryotic proteome consisting of multidomain proteins, how is inter-domain misfolding avoided? It has been proposed that maintaining low sequence identity between covalently linked domains is a mechanism to avoid misfolding. Here we use single-molecule Förster Resonance Energy Transfer (FRET) experiments to detect and quantify rare misfolding events in tandem Ig domains from the I-band of titin under native conditions. About 5.5% of molecules with identical domains misfold during refolding in vitro and form a surprisingly stable state with an unfolding half time of several days. Tandem arrays of immunoglobulin-like (Ig-like) domains in humans exhibit significantly lower sequence identity between neighbouring domains than between non-adjacent domains. In particular, the sequence identity of neighbouring domains has been found to be preferentially below 40%. Interestingly we observe no misfolding for a tandem of naturally neighbouring domains with low sequence identity (24%), whereas misfolding occurs between domains which are 42% identical. Coarse-grained molecular simulations predict the formation of domain-swapped structures, which are in excellent agreement with the observed transfer efficiency of the misfolded species. We infer that the interactions underlying misfolding are very specific and result in a sequence-specific domain swapping mechanism. Diversifying the sequence between neighbouring domains appears to be a successful evolutionary strategy to avoid misfolding in multidomain proteins.
登录
查看更多内容
影响因子：
56.9
作者：
Korzhnev, Dmitry M.;Religa, Tomasz L.;Kay, Lewis E.
通讯作者：
Kay, Lewis E.
影响因子：
5.7
作者：
Improta, S;Politou, AS;Pastore, A
通讯作者：
Pastore, A
影响因子：
3
作者：
BROOKS, BR;BRUCCOLERI, RE;KARPLUS, M
通讯作者：
KARPLUS, M
DOI：
10.1073/pnas.0904461106
发表时间：
2009-06-23
影响因子：
11.1
作者：
Gambin, Yann;Schug, Alexander;Deniz, Ashok A.
通讯作者：
Deniz, Ashok A.
影响因子：
16.8
作者：
Gianni, Stefano;Ivarsson, Ylva;Vendruscolo, Michele
通讯作者：
Vendruscolo, Michele