Influence of repeat numbers on self-assembly rates of repetitive recombinant spider silk proteins
Influence of repeat numbers on self-assembly rates of repetitive recombinant spider silk proteins
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DOI：
10.1016/j.jsb.2014.03.010
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发表时间：
2014-06-01
影响因子：
3
通讯作者：
Scheibel, Thomas
中科院分区：
文献类型：
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作者：
Humenik, Martin;Magdeburg, Michael;Scheibel, Thomas
重组蜘蛛丝变体 eADF4(Cn) 包含不同数量 (n) 的共有序列基序 C（源自天然 Araneus diadematus 拖丝 ADF4），在 n >= 2 的情况下产生无法区分的纳米原纤维。C 模块包含 35 个富含甘氨酸和脯氨酸残基的氨基酸（在 GPGXY 重复中）和一段聚丙氨酸 (Ala)(8)。发现所有变体在溶液中本质上是无序的，并且在原纤维形成后它们转化为交叉β结构。异源接种表明不同 eADF4(Cn) 变体之间具有高度的结构兼容性，然而，它们的组装动力学因重复次数而异。动力学分析揭示了交叉β原纤维形成的典型成核生长机制，成核速率和生长速率随着重复次数的增加而增加。引人注目的是，单个 C 模块不会自组装成原纤维，但在添加异源种子后，可以观察到原纤维的生长。显然，至少两个C-模块的互连显着促进了从无序状态到β-折叠结构的结构转变，这对于成核是必要的并且有利于原纤维生长。 (C) 2014 Elsevier Inc. 保留所有权利。
Assembly of recombinant spider silk variants eADF4(Cn) comprising different numbers (n) of the consensus sequence motif C, derived from the natural Araneus diadematus dragline silk ADF4, yielded indistinguishable nanofibrils in cases of n >= 2. The C-module comprises 35 amino acids rich in glycine and proline residues (in GPGXY repeats) and one polyalanine stretch (Ala)(8). All variants were found to be intrinsically disordered in solution, and upon fibril formation they converted into a cross-beta structure. Heterologous seeding indicated high structural compatibility between the different eADF4(Cn) variants, however, their assembly kinetics differed in dependence of the number of repeats. Kinetic analysis revealed a nucleation-growth mechanism typical for the formation of cross-beta-fibrils, with nucleation rates as well as growth rates increasing with increasing numbers of repeats. Strikingly, the single C-module did not self-assemble into fibrils, but upon addition of heterologous seeds fibril growth could be observed. Apparently, interconnecting of at least two C-modules significantly facilitates the structural transformation from a disordered state into beta-sheet structures, which is necessary for nucleation and beneficial for fibril growth. (C) 2014 Elsevier Inc. All rights reserved.