Antimicrobial Activity and Bacterial-Membrane Interaction of Ovine-Derived Cathelicidins

Abstract

Three ovine-derived cathelicidins, SMAP29, OaBac5mini, and OaBac7.5mini, were compared with respect to their antibacterial activities and interactions with membranes. SMAP29 was confirmed to be ␣-helical, broad spectrum, and able to disrupt both the outer and the cytoplasmic membranes at relatively low concentrations. In contrast, the two proline-and arginine-rich OaBac peptides had more-modest antibacterial activities, reduced levels of lipopolysaccharide binding, and a lesser ability to depolarize the cytoplasmic membrane, consistent with a cytoplasmic target.

ChBac3.4: A Novel Proline-Rich Antimicrobial Peptide from Goat Leukocytes

“…The results obtained by the broth microdilution assay allowed to compare the activity of ChBac5 with previously described bovine Bac5 and Bac7 (Gennaro et al 1989) and ovine Bac5 which were tested in similar conditions. The activity of ChBac3.4 against gramnegative bacteria closely matched to that of ChBac5 and that described for bovine Bac5, Bac7 and their N-terminal fragments (Gennaro et al 1989;Podda et al 2006;Benincasa et al 2004); and to the activity of Bac5, OaBac5mini and OaBac7.5mini of sheep (Anderson and Yu 2003;Anderson et al 2004). Conversely, ChBac3.4 was significantly more active against gram-positive bacteria than ChBac5 as well as than bovine Bac5, Bac7 and somewhat more active than a 24-residues N-terminal fragment of ovine Bac5 (OaBac5mini) and OaBac7.5mini, which also demonstrated some effects in respect with Staphylococci (Anderson et al 2004).…”

Potential of Novel Antimicrobial Peptide P3 from Bovine Erythrocytes and Its Analogs To Disrupt Bacterial Membranes In Vitro and Display Activity against Drug-Resistant Bacteria in a Mouse Model

“…It is known that AMPs, including SMAP29 and LL-37, can permeabilize the bacterial cytoplasmic membrane (26,27), as did P3, which created many membrane pores in the E. coli membrane, in line with the barrel stave model (28). It is generally considered that AMPs exhibiting potent antimicrobial activities also have strong hemolytic and cytotoxic activities (29).…”

Activity of the De Novo Engineered Antimicrobial Peptide WLBU2 against Pseudomonas aeruginosa in Human Serum and Whole Blood: Implications for Systemic Applications

“…The interactions of CAPs with their microbial targets are thought to occur electrostatically, mediated by lipid molecules on bacterial surfaces (3,23,34,35). Numerous studies of CAP interactions with variably charged liposomes suggest that antimicrobial peptides selectively bind bacterial over eukaryotic cell membranes because of the negatively charged lipids found on the outer leaflets of the former (10,20).…”

“…These ubiquitous peptides typically consist of 20 to 40 amino acid residues and are highly cationic. Most host-derived CAPs display broad activity against both gram-positive and gramnegative bacteria (3,4,6,8,13).…”

“…Cationic amphipathic peptides (CAPs) have been extensively investigated as a potential source of these agents (22,26,37,44) and are a major class of antimicrobial peptides with different secondary structures (␣-helix, ␤-sheets, loops, etc.) that provide neutrophils and epithelial surfaces of multicellular organisms with a rapid and efficient means of inactivating invading pathogens (3,28,29,39,49,58,59,62). These ubiquitous peptides typically consist of 20 to 40 amino acid residues and are highly cationic.…”