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Amyloid fibers provide structural integrity to Bacillus subtilis biofilms.

ABSTRACT: 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.

SUBMITTER: Romero D

PROVIDER: S-EPMC2836674 | biostudies-literature | 2010 Feb

REPOSITORIES: biostudies-literature

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Amyloid fibers provide structural integrity to Bacillus subtilis biofilms.

Romero Diego D Aguilar Claudio C Losick Richard R Kolter Roberto R

Proceedings of the National Academy of Sciences of the United States of America 20100113 5

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 ...[more]

PMID: 20080671

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