The extracellular matrix of biofilms provides crucial structural support to the community and protection from environmental perturbations. TasA, a key Bacillus subtilis biofilm matrix protein, forms both amyloid and non-amyloid fibrils. Non-amyloid TasA fibrils are formed via a strand-exchange mechanism, whereas the amyloid-like form involves non-specific self-assembly. We performed mutagenesis of the N-terminus to assess the role of non-amyloid fibrils in biofilm development. We find that the N-terminal tail is essential for the formation of structured biofilms, providing evidence that the strand-exchange fibrils are the active form in the biofilm matrix. Furthermore, we demonstrate that fibre formation alone is not sufficient to give structure to the biofilm. We build an interactome of TasA with other extracellular protein components, and identify important interaction sites. Our results provide insight into how protein–matrix interactions modulate biofilm development.

中文翻译：

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TasA 纤维相互作用对于枯草芽孢杆菌生物膜结构是必需的


生物膜的细胞外基质为群落提供重要的结构支持，并保护其免受环境扰动。TasA 是一种关键的枯草芽孢杆菌生物膜基质蛋白，可形成淀粉样蛋白和非淀粉样蛋白原纤维。非淀粉样蛋白 TasA 原纤维是通过链交换机制形成的，而淀粉样蛋白形式涉及非特异性自组装。我们进行了 N 端的诱变，以评估非淀粉样蛋白原纤维在生物膜发育中的作用。我们发现 N 末端尾部对于结构化生物膜的形成至关重要，这提供了链交换原纤维是生物膜基质中的活性形式的证据。此外，我们证明仅靠纤维形成不足以赋予生物膜结构。我们构建了 TasA 与其他细胞外蛋白成分的相互作用组，并确定了重要的相互作用位点。我们的结果为蛋白质-基质相互作用如何调节生物膜发育提供了见解。