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Publication Abstract from PubMed

The amyloid-antimicrobial link hypothesis is based on antimicrobial properties found in human amyloids involved in neurodegenerative and systemic diseases, along with amyloidal structural properties found in antimicrobial peptides (AMPs). Supporting this hypothesis, we here determined the fibril structure of two AMPs from amphibians, uperin 3.5 and aurein 3.3, by cryogenic electron microscopy (cryo-EM), revealing amyloid cross-beta fibrils of mated beta-sheets at atomic resolution. Uperin 3.5 formed a 3-blade symmetrical propeller of nine peptides per fibril layer including tight beta-sheet interfaces. This cross-beta cryo-EM structure complements the cross-alpha fibril conformation previously determined by crystallography, substantiating a secondary structure switch mechanism of uperin 3.5. The aurein 3.3 arrangement consisted of six peptides per fibril layer, all showing kinked beta-sheets allowing a rounded compactness of the fibril. The kinked beta-sheets are similar to LARKS (Low-complexity, Amyloid-like, Reversible, Kinked Segments) found in human functional amyloids.

The Cryo-EM structures of two amphibian antimicrobial cross-beta amyloid fibrils.,Bucker R, Seuring C, Cazey C, Veith K, Garcia-Alai M, Grunewald K, Landau M Nat Commun. 2022 Jul 27;13(1):4356. doi: 10.1038/s41467-022-32039-z. PMID:35896552^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.