1.D.194.  The Intestinalin (P30) Peptide Derived from LysC of Clostridium intestinale Strain URNW (Intestinalin) Family

The LysC autolysin from Clostridium intestinale URNW (GenBank ERK30183.1) and the peptide Intestinalin (P30) derived from the LysC N-terminal region (aas: KNLLRRIRRKLRNKFSRSDVIKTPKIVEVN), against Staphylococcus aureus ATCC 25923, proved to be effective at a 5 μM concentration while the intact LysC protein was effective at a 4-fold higher concentration (21 μM) (Szadkowska et al. 2022). This peptide is also effective against a wide range of Gram- and Gram+ bacteria. Although positively charged, Intestinalin resides in the membrane and aggregates into small oligomers. Negatively charged phospholipids stabilize peptide oligomers to form water- and ion-permeable pores, disrupting the integrity of bacterial cell membranes. It causes membrane depolarization and affects membrane integrity by forming large pores, resulting in loss of bacterial viability (Szadkowska et al. 2022).

Antimicrobial peptides (AMPs) are a class of small peptides that widely exist in nature, and they are an important part of the innate immune system of certain organisms. AMPs have a wide range of inhibitory effects against bacteria, fungi, parasites and viruses, and some of these exert their effects by increasing membrane permeability.  These peptides may act via several very different mechanisms (Bahar and Ren 2013) (Huan et al. 2020).