Toxic Misfolded Transthyretin Oligomers with Different Molecular Conformations Formed through Distinct Oligomerization Pathways.
Toxic Misfolded Transthyretin Oligomers with Different Molecular Conformations Formed through Distinct Oligomerization Pathways.
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DOI：
10.1021/acs.biochem.2c00390
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发表时间：
2022-11-01
期刊：
影响因子：
2.9
通讯作者：
Lim, Kwang Hun
中科院分区：
文献类型：
--
作者：
Dasari, Anvesh K. R.;Yi, Sujung;Coats, Matthew F.;Wi, Sungsool;Lim, Kwang Hun
蛋白质聚集是由天然多肽到细胞毒性寡聚体的结构变化引发的，其形成交叉β结构的淀粉样蛋白。低聚物中间体的鉴定和表征对于理解淀粉样蛋白低聚物聚集的分子机制以及细胞毒性性质至关重要。然而，制备用于结构表征的错误折叠的低聚物是具有挑战性的，因为它们是瞬时的、异质的。在这里，我们报告两个不同的错误折叠甲状腺素运载蛋白（TTR）寡聚体通过不同的寡聚化途径形成。一个致病TTR变体具有较强的聚集倾向（L55 P）被用来制备错误折叠的低聚物在生理pH值。我们的机制研究表明，全长TTR最初形成小的低聚物，自组装成短的原纤维在后期阶段。CD环的酶促裂解也用于诱导N-末端截短的寡聚体的形成，其在从患者组织提取的离体心脏TTR聚集体中检测到。使用固态NMR和圆二色性的低聚物的结构表征表明，两个TTR错误折叠的低聚物具有不同的分子构象。此外，蛋白水解裂解的TTR寡聚体表现出更高的表面疏水性，表明存在不同的寡聚化途径的TTR寡聚体形成。细胞毒性试验还显示，裂解的寡聚体具有比全长TTR寡聚体更强的细胞毒性，表明疏水性可能是毒性寡聚体的重要性质。这些比较生物物理分析表明，通过不同的错折叠途径形成的毒性切割TTR寡聚体可能采用不同的结构特征，产生更高的表面疏水性，导致更强的细胞毒性活性。
Protein aggregation is initiated by structural changes from native polypeptides to cytotoxic oligomers, which form cross-β structured amyloid. Identification and characterization of oligomeric intermediates is of critical importance to understand not only molecular mechanism of aggregation, but also cytotoxic nature of amyloid oligomers. Preparation of misfolded oligomers for structural characterization is, however, challenging because of their transient, heterogeneous nature. Here, we report two distinct misfolded transthyretin (TTR) oligomers formed through different oligomerization pathways. A pathogenic TTR variant with strong aggregation propensity (L55P) was used to prepare misfolded oligomers at the physiological pH. Our mechanistic studies showed that the full-length TTR initially forms small oligomers, which self-assemble into short protofibrils at later stages. Enzymatic cleavage of the CD loop was also used to induce the formation of N-terminally truncated oligomers, which was detected in ex vivo cardiac TTR aggregates extracted from patient’s tissues. Structural characterization of the oligomers using solid-state NMR and circular dichroism revealed that the two TTR misfolded oligomers have distinct molecular conformations. In addition, the proteolytically cleaved TTR oligomers exhibit a higher surface hydrophobicity, suggesting the presence of distinct oligomerization pathways for the TTR oligomer formation. Cytotoxicity assays also revealed that the cleaved oligomers have stronger cytotoxicity than the full-length TTR oligomers, indicating that hydrophobicity might be an important property of toxic oligomers. These comparative biophysical analyses suggest that the toxic cleaved TTR oligomers formed through a different misfoling pathway may adopt distinct structural features that produce higher surface hydrophobicity, leading to the stronger cytotoxic activities.
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影响因子：
16.6
作者：
Cascella R;Chen SW;Bigi A;Camino JD;Xu CK;Dobson CM;Chiti F;Cremades N;Cecchi C
通讯作者：
Cecchi C
DOI：
10.3390/molecules25235698
发表时间：
2020-12-03
期刊：
Molecules (Basel, Switzerland)
影响因子：
--
作者：
Frangolho A;Correia BE;Vaz DC;Almeida ZL;Brito RMM
通讯作者：
Brito RMM
DOI：
10.1073/pnas.1421204112
发表时间：
2015-04-21
影响因子：
11.1
作者：
Chen, Serene W.;Drakulic, Srdja;Cremades, Nunilo
通讯作者：
Cremades, Nunilo
DOI：
10.1073/pnas.0610313104
发表时间：
2007-06-05
影响因子：
11.1
作者：
Cavalli, Andrea;Salvatella, Xavier;Vendruscolo, Michele
通讯作者：
Vendruscolo, Michele
影响因子：
2.9
作者：
COLON, W;KELLY, JW
通讯作者：
KELLY, JW