Amyloid fibers provide structural integrity to Bacillus subtilis biofilms
Amyloid fibers provide structural integrity to Bacillus subtilis biofilms
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DOI：
10.1073/pnas.0910560107
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发表时间：
2010-02-02
影响因子：
11.1
通讯作者：
Kolter, Roberto
中科院分区：
文献类型：
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作者：
Romero, Diego;Aguilar, Claudio;Kolter, Roberto
枯草芽孢杆菌形成生物膜，其组成细胞通过细胞外基质保持在一起。以前的研究表明，蛋白质TasA和胞外多糖是基质的主要成分。鉴于TasA在生物膜形成中的重要性，我们表征了这种蛋白质的理化性质。我们报告说，纯化的TasA形式的可变长度和10-15 nm的宽度的纤维。生化分析，结合使用特定的染料和显微镜分析，表明TasA形成淀粉样纤维。与这一假设一致，TasA纤维需要苛刻的处理（例如，甲酸）进行解聚。当添加到tasA突变体的培养物中时，纯化的TasA恢复了野生型生物膜形态，表明纯化的蛋白质保留了生物活性。我们认为TasA形成淀粉样纤维，将生物膜中的细胞结合在一起。
Bacillus subtilis forms biofilms whose constituent cells are held together by an extracellular matrix. Previous studies have shown that the protein TasA and an exopolysaccharide are the main components of the matrix. Given the importance of TasA in biofilm formation, we characterized the physicochemical properties of this protein. We report that purified TasA forms fibers of variable length and 10-15 nm in width. Biochemical analyses, in combination with the use of specific dyes and microscopic analyses, indicate that TasA forms amyloid fibers. Consistent with this hypothesis, TasA fibers required harsh treatments (e.g., formic acid) to be depolymerized. When added to a culture of a tasA mutant, purified TasA restored wild-type biofilm morphology, indicating that the purified protein retained biological activity. We propose that TasA forms amyloid fibers that bind cells together in the biofilm.