Detalle de: The amphibian antimicrobial peptide uperin 3.5 is a cross-α/cross-β chameleon functional amyloid

Significance We determined the crystal structure of the full-length amphibian antimicrobial peptide (AMP) uperin 3.5 and showed fibrillation into helical “cross-α” amyloid fibril, correlated with its antibacterial activity. This provides a molecular basis for the link between AMPs which are largely helical in nature, and amyloid formation. Uperin 3.5 is a cross-α amyloid discovered in eukaryotes, following a previously reported cross-α amyloid fibril for Staphylococcus aureus PSMα3 cytotoxin, hence demonstrating the existence of the cross-α amyloid architecture across kingdoms of life, with potential functional roles in early evolution. Furthermore, the findings revealed a chameleon cross-α/cross-β secondary structure switch of uperin 3.5 fibrils, likely related to regulation of its activity.

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