Unusual structural transition of antimicrobial VP1 peptide

VP1 peptide, an active domain of m-calpain enzyme with antimicrobial activity is found to undergo an unusual conformational transition in trifluoroethanol (TFE) solvent. The nature of, and time dependent variations in, circular dichroism associated with the amide I vibrations, suggest that VP1 undergoes self-aggregation forming anti-parallel β-sheet structure in TFE. Transmission electron micrograph (TEM) images revealed that β-sheet aggregates formed by VP1 possess fibril-like assemblies.

Research Highlights► VP1 peptide exhibits antiparallel b-sheet structure, forming fibrils in TFE. ► TEM images confirm fibril type assemblages. ► First antimicrobial peptide to exhibit fibril type assemblages. ► Need for further investigations of m-calpain activity.