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bioRxiv · 10.1101/309062

Extreme Amyloid Polymorphism in Staphylococcus aureus Virulent PSMα Peptides

Salinas, N.·Colletier, J.-P.·Moshe, A.·Landau, M.
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Abstract

Members of the Staphylococcus aureus phenol-soluble modulin (PSM) peptide family are secreted as functional amyloids that serve diverse roles in pathogenicity and may be present as full-length peptides or as naturally occurring truncations. We recently showed that the activity of PSM3, the most toxic member, stems from the formation of cross- fibrils, which are at variance with the cross-{beta} fibrils linked with eukaryotic amyloid pathologies. Here, we show that PSM1 and PSM4, involved in biofilm structuring, form canonical cross-{beta} amyloid fibrils wherein {beta}-sheets tightly mate through steric zipper interfaces, conferring high stability. Contrastingly, a truncated PSM3 has antibacterial activity, forms reversible fibrils, and reveals two polymorphic and atypical {beta}-rich fibril architectures. These architectures are radically different from both the cross- fibrils formed by full-length PSM3, and from the canonical cross-{beta} fibrils. Our results point to structural plasticity being at the basis of the functional diversity exhibited by S. aureus PSMs.

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Salinas, N., Colletier, J.-P., Moshe, A., Landau, M.. 2018-04-26. Extreme Amyloid Polymorphism in Staphylococcus aureus Virulent PSMα Peptides. https://doi.org/10.1101/309062

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