Modular genetic design of multi-domain functional amyloids: insights into self-assembly and functional properties
Modular genetic design of multi-domain functional amyloids: insights into self-assembly and functional properties
复制标题
多域功能淀粉样蛋白的模块化遗传设计：洞察自组装和功能特性
DOI：
10.1039/c9sc00208a
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发表时间：
2019-04-14
期刊：
影响因子：
8.4
通讯作者：
Zhong, Chao
中科院分区：
文献类型：
--
作者：
Cui, Mengkui;Qi, Qi;Zhong, Chao
通过模块化遗传策略工程化功能性淀粉样蛋白代表了创造具有定制结构和性能的多功能分子材料的新机会。尽管取得了重要进展，但融合模块如何影响淀粉样蛋白的自组装和功能特性仍然难以捉摸。本文以大肠杆菌curli为模型系统，系统地研究了侧翼结构域对淀粉样蛋白结构、组装动力学和功能的影响。设计的淀粉样蛋白由E.大肠杆菌生物膜蛋白CsgA（作为淀粉样核心）和一个或两个侧翼结构域，其由来自环状芽孢杆菌几丁质酶的几丁质结合结构域（CBD）和/或贻贝足蛋白（Mfps）组成。融合域的掺入并没有破坏典型的片层结构，但确实影响了组装速率，形态和所得原纤维的刚度。因此，CsgA融合原纤维，特别是含有三个结构域的那些，比仅CsgA的原纤维短得多。此外，所得到的原纤维的刚度受到严重影响的融合域的结构特征，与-片含域趋于增加杨氏模量，而随机卷曲域降低杨氏模量。此外，含有CBD结构域的原纤维显示出更高的几丁质结合活性相比，其CBD自由的同行。CBD-CsgA-Mfp 3构建体表现出比Mfp 5-CsgA-CBD显著更低的结合活性，这是由于前者构建体中CBD结构域的不适当折叠，与基于分子动力学建模的结果一致。我们的研究为设计师淀粉样蛋白的组装和功能特性提供了新的见解，并为未来设计功能性淀粉样蛋白结构和分子材料奠定了基础。
Engineering functional amyloids through a modular genetic strategy represents new opportunities for creating multifunctional molecular materials with tailored structures and performance. Despite important advances, how fusion modules affect the self-assembly and functional properties of amyloids remains elusive. Here, using Escherichia coli curli as a model system, we systematically studied the effect of flanking domains on the structures, assembly kinetics and functions of amyloids. The designed amyloids were composed of E. coli biofilm protein CsgA (as amyloidogenic cores) and one or two flanking domains, consisting of chitin-binding domains (CBDs) from Bacillus circulans chitinase, and/or mussel foot proteins (Mfps). Incorporation of fusion domains did not disrupt the typical -sheet structures, but indeed affected assembly rate, morphology, and stiffness of resultant fibrils. Consequently, the CsgA-fusion fibrils, particularly those containing three domains, were much shorter than the CsgA-only fibrils. Furthermore, the stiffness of the resultant fibrils was heavily affected by the structural feature of fusion domains, with -sheet-containing domains tending to increase the Young's modulus while random coil domains decreasing the Young's modulus. In addition, fibrils containing CBD domains showed higher chitin-binding activity compared to their CBD-free counterparts. The CBD-CsgA-Mfp3 construct exhibited significantly lower binding activity than Mfp5-CsgA-CBD due to inappropriate folding of the CBD domain in the former construct, in agreement with results based upon molecular dynamics modeling. Our study provides new insights into the assembly and functional properties of designer amyloid proteins with increasing complex domain structures and lays the foundation for the future design of functional amyloid-based structures and molecular materials.