Identification and antibacterial activity of a novel antimicrobial peptide attacin from Conogethes punctiferalis.

The escalating antimicrobial resistance crisis has propelled bacterial infections to the forefront of global health challenges. Therefore, it is particularly important to develop new antimicrobial drugs, such as antimicrobial peptides. The present study aims to characterize a novel attacin-like antimicrobial peptide and explore its antibacterial mechanism against Staphylococcus aureus (S. aureus). In this study, a novel attacin, referred to as CpAtt, was identified from Conogethes punctiferalis (C. punctiferalis). CpAtt was characterized by bioinformatics analysis and in vitro experiments. The results suggested that the novel attacin CpAtt owned an open reading frame (ORF) of 609 bp in length, encoding 202 amino acids. Sequence alignment and homology modeling analysis revealed that CpAtt formed a β-barrel structure with electrostatic heterogeneity, suggesting a potential pore-forming mechanism through transmembrane disruption. The recombinant protein CpAtt exhibits preferential efficacy against Gram-positive bacteria. SEM observation proved that S. aureus treated with CpAtt exhibits severe deformities. Molecular docking analysis predicted that CpAtt might bind to Lipid II and lipoteichoic acid. However, CpAtt was determined to have concentration-dependent hemolytic activity. This study identified a novel attacin, CpAtt, and successfully expressed CpAtt in E. coli, exhibiting effective antibacterial activity on Gram-positive bacteria, which establishes a robust foundation for the precise elucidation of CpAtt's antibacterial mechanisms and optimization of derived peptide design.