Adhesion mechanisms of curli subunit CsgA to abiotic surfaces.
Adhesion mechanisms of curli subunit CsgA to abiotic surfaces.
复制标题
卷质亚基CSGA的粘附机制对非生物表面。
DOI：
10.1126/sciadv.1600998
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发表时间：
2016-11
期刊：
影响因子：
13.6
通讯作者：
Keten S
中科院分区：
文献类型：
--
作者：
DeBenedictis EP;Liu J;Keten S
卷曲纤维亚基，CsgA，坚持强烈的非生物表面通过侧链相互作用，也表现出相关的运动。卷曲纤维是功能性淀粉样蛋白，在生物膜结构和粘附到各种表面中起关键作用。最近已经产生了包含curli纤维的强生物启发粘合剂;然而，curli用于附着到非生物表面上的机制仍然没有被表征。对于基于curli的粘合剂和多功能材料的材料设计方法，我们通过原子模拟研究curli亚基吸附到石墨烯和二氧化硅表面上。我们发现，结构特征和序列的影响粘附强度，使CsgA亚基坚持强烈的极性和非极性表面。具体而言，柔性区域促进粘附到两个表面，带电和极性残基（Arg、Lys和Gln）能够与二氧化硅发生强相互作用，并且六碳芳环（Tyr和Phe）强烈吸附到石墨烯。我们发现，吸附不仅降低分子的流动性，但也导致损失的二级结构，必须很好地平衡有效的表面附着的因素。这两个事件似乎通过CsgA结构传播，作为残基簇之间的相关运动，通常在相邻β链上的行之间H键合。为了量化这一点，我们提出了一个相关性分析的方法来检测残留物组之间的集体运动。我们发现某些残基簇对蛋白质结构的其余部分的稳定性具有更高的影响，通常是螺旋核心内的极性和庞大基团。这些发现有助于深入了解细菌的粘附机制，并揭示了理论驱动的工程卷曲纤维设计策略，这些纤维利用点突变和缀合物实现更强的粘附。
The curli fiber subunit, CsgA, adheres strongly to abiotic surfaces through side-chain interactions and also exhibits correlated motion. Curli fibers are functional amyloids that play a key role in biofilm structure and adhesion to various surfaces. Strong bioinspired adhesives comprising curli fibers have recently been created; however, the mechanisms curli uses to attach onto abiotic surfaces are still uncharacterized. Toward a materials-by-design approach for curli-based adhesives and multifunctional materials, we examine curli subunit adsorption onto graphene and silica surfaces through atomistic simulation. We find that both structural features and sequence influence adhesive strength, enabling the CsgA subunit to adhere strongly to both polar and nonpolar surfaces. Specifically, flexible regions facilitate adhesion to both surfaces, charged and polar residues (Arg, Lys, and Gln) enable strong interactions with silica, and six-carbon aromatic rings (Tyr and Phe) adsorb strongly to graphene. We find that adsorption not only lowers molecular mobility but also leads to loss of secondary structure, factors that must be well balanced for effective surface attachment. Both events appear to propagate through the CsgA structure as correlated motion between clusters of residues, often H-bonded between rows on adjacent β strands. To quantify this, we present a correlation analysis approach to detecting collective motion between residue groups. We find that certain clusters of residues have a higher impact on the stability of the rest of the protein structure, often polar and bulky groups within the helix core. These findings lend insight into bacterial adhesion mechanisms and reveal strategies for theory-driven design of engineered curli fibers that harness point mutations and conjugates for stronger adhesion.