7OAG

Cryo-EM structure of the plectasin fibril (single strand)

Summary for 7OAG

• Entry DOI: 10.2210/pdb7oag/pdb
• EMDB information: 12776
• Descriptor: Fungal defensin plectasin (1 entity in total)
• Functional Keywords: fibril, helical, antimicrobial protein
• Biological source: Pseudoplectania nigrella (Ebony cup)
• Total number of polymer chains: 25
• Total formula weight: 110052.30

Authors

Effantin, G. (deposition date: 2021-04-19, release date: 2022-04-27, Last modification date: 2025-07-02)

Primary citation

Pohl, C.,Effantin, G.,Kandiah, E.,Meier, S.,Zeng, G.,Streicher, W.,Segura, D.R.,Mygind, P.H.,Sandvang, D.,Nielsen, L.A.,Peters, G.H.J.,Schoehn, G.,Mueller-Dieckmann, C.,Noergaard, A.,Harris, P.
pH- and concentration-dependent supramolecular assembly of a fungal defensin plectasin variant into helical non-amyloid fibrils.
Nat Commun, 13:3162-3162, 2022

PubMed Abstract: Self-assembly and fibril formation play important roles in protein behaviour. Amyloid fibril formation is well-studied due to its role in neurodegenerative diseases and characterized by refolding of the protein into predominantly β-sheet form. However, much less is known about the assembly of proteins into other types of supramolecular structures. Using cryo-electron microscopy at a resolution of 1.97 Å, we show that a triple-mutant of the anti-microbial peptide plectasin, PPI42, assembles into helical non-amyloid fibrils. The in vitro anti-microbial activity was determined and shown to be enhanced compared to the wildtype. Plectasin contains a cysteine-stabilised α-helix-β-sheet structure, which remains intact upon fibril formation. Two protofilaments form a right-handed protein fibril. The fibril formation is reversible and follows sigmoidal kinetics with a pH- and concentration dependent equilibrium between soluble monomer and protein fibril. This high-resolution structure reveals that α/β proteins can natively assemble into fibrils.

PubMed: 35672293
DOI: 10.1038/s41467-022-30462-w

Experimental method

ELECTRON MICROSCOPY (3.4 Å)