Cationic antimicrobial peptides characteristics

As many of the phenotypic changes induced following PhoPQ activation involve host defense peptide resistance characteristics, it is postulated that host defense peptides serve as an endogenous ligand for PhoQ Indeed, the exposure of S. typhimurium to sublethal concentrations of cationic antimicrobial peptides results in activation of the PhoPI regulon and host defense peptide resistance phenotypes. " Supporting... 

Defensins, potent antimicrobial and proin-flammatory peptides antimicrobial peptides). Mammalian defensins are cationic peptides (Mr 3.5. 5 kDa), rich in lysine and arginine containing six cysteine residues which form three characteristic disulfide bridges. According to the alignment of the disulfide bonds and the overall structure, defensins can be divided into three groups a-defensins, /S-defensins, and 0-defensins. Antimicrobial peptides of plants or insects have also been termed defensins, though they have different structural features in comparison to vertebrate defensins. a-Defensins consist of... 

Structure-activity relationship studies investigating the antimicrobial activities of host defense peptides have primarily sought the characterization of the specific sequence/structural motifs that dictate antimicrobial and cytotoxic activities. Perhaps unsurprisingly these activities appear to be dictated by a delicate balance of cationicity, hydrophobicity, amphipathicity, and ultimately the structural characteristics of the peptides. 

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