Recombinant Expression and Antimicrobial Mechanism of Cysteine-Rich Antimicrobial Peptides from Tigriopus japonicus Genome

The misuse of antibacterial agents has contributed to the growing prevalence of antibiotic resistance, highlighting an urgent need to explore alternative anti-infection therapeutic strategies. Antimicrobial peptides (AMPs) are naturally occurring molecules. They exhibit broad-spectrum antimicrobial activity and represent promising candidates for the development of novel therapeutics. A cysteine-rich antimicrobial peptide was identified and characterized from the genome of <i>Tigriopus japonicus</i> and designated "<i>Tj</i>Rcys1". The precursor form of <i>Tj</i>Rcys1 comprises 96 amino acids. Structural analyses of <i>Tj</i>Rcys1 revealed random coils, two α-helices, and two β-strands. Recombinant <i>Tj</i>Rcys1 had inhibitory effects upon <i>Staphylococcus aureus</i> and <i>Bacillus</i> sp. T2, with a minimum inhibitory concentration of 64 μM for both. <i>Tj</i>Rcys1 did not show complete inhibition against <i>Vibrio alginolyticus</i>, <i>Klebsiella pneumoniae</i>, or <i>Aeromonas hydrophila</i> at 64 μM, but it did slow their growth rate. <i>Tj</i>Rcys1 could disrupt the permeability of the cell membrane of <i>S. aureus</i>. Transcriptomic analyses indicated that <i>Tj</i>Rcys1 could interfere with the ribosome biosynthesis and nucleotide metabolism of <i>K. pneumoniae</i>. Our results provide a valuable reference for the development of new AMPs and optimization of their design.