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

## TL;DR

This paper identifies and characterizes a new antimicrobial peptide from the genome of Tigriopus japonicus, showing its potential as an alternative to traditional antibiotics.

## Contribution

The discovery and characterization of a novel cysteine-rich antimicrobial peptide, TjRcys1, from the genome of Tigriopus japonicus.

## Key findings

- TjRcys1 effectively inhibits the growth of Staphylococcus aureus and Bacillus sp. T2 at 64 μM.
- TjRcys1 disrupts the cell membrane permeability of S. aureus and affects ribosome biosynthesis and nucleotide metabolism in K. pneumoniae.
- TjRcys1 shows partial inhibition of Vibrio alginolyticus, Klebsiella pneumoniae, and Aeromonas hydrophila at 64 μM.

## Abstract

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 Tigriopus japonicus and designated “TjRcys1”. The precursor form of TjRcys1 comprises 96 amino acids. Structural analyses of TjRcys1 revealed random coils, two α-helices, and two β-strands. Recombinant TjRcys1 had inhibitory effects upon Staphylococcus aureus and Bacillus sp. T2, with a minimum inhibitory concentration of 64 μM for both. TjRcys1 did not show complete inhibition against Vibrio alginolyticus, Klebsiella pneumoniae, or Aeromonas hydrophila at 64 μM, but it did slow their growth rate. TjRcys1 could disrupt the permeability of the cell membrane of S. aureus. Transcriptomic analyses indicated that TjRcys1 could interfere with the ribosome biosynthesis and nucleotide metabolism of K. pneumoniae. Our results provide a valuable reference for the development of new AMPs and optimization of their design.