Fowlicidin-3 is an alpha-helical cationic host defense peptide with potent antibacterial and lipopolysaccharide-neutralizing activities.
Bommineni, Y.R., Dai, H., Gong, Y.X., Soulages, J.L., Fernando, S.C., Desilva, U., Prakash, O., Zhang, G.(2007) FEBS J 274: 418-428
- PubMed: 17229147 
- DOI: https://doi.org/10.1111/j.1742-4658.2006.05589.x
- Primary Citation of Related Structures:  
2HFR - PubMed Abstract: 
Cathelicidins are an important family of cationic host defense peptides in vertebrates with both antimicrobial and immunomodulatory activities. Fowlicidin-1 and fowlicidin-2 are two newly identified chicken cathelicidins with potent antibacterial activities. Here we report structural and functional characterization of the putatively mature form of the third chicken cathelicidin, fowlicidin-3, for exploration of its therapeutic potential. NMR spectroscopy revealed that fowlicidin-3 comprises 27 amino-acid residues and adopts a predominantly alpha-helical structure extending from residue 9 to 25 with a slight kink induced by a glycine at position 17. It is highly potent against a broad range of Gram-negative and Gram-positive bacteria in vitro, including antibiotic-resistant strains, with minimum inhibitory concentrations in the range 1-2 microM. It kills bacteria quickly, permeabilizing cytoplasmic membranes immediately on coming into contact with them. Unlike many other host defense peptides with antimicrobial activities that are diminished by serum or salt, fowlicidin-3 retains bacteria-killing activities in the presence of 50% serum or physiological concentrations of salt. Furthermore, it is capable of suppressing lipopolysaccharide-induced expression of proinflammatory genes in mouse macrophage RAW264.7 cells, with nearly complete blockage at 10 microM. Fowlicidin-3 appears to be an excellent candidate for future development as a novel antimicrobial and antisepsis agent, particularly against antibiotic-resistant pathogens.
Organizational Affiliation: 
Department of Animal Science, Oklahoma State University, Stillwater, OK 74078, USA.