Identification of a novel cathelicidin antimicrobial peptide from ducks and determination of its functional activity and antibacterial mechanism

Abstract

The family of antimicrobial peptide, cathelicidins, which plays important roles against infections in animals, has been identified from many species. Here, we identified a novel avian cathelicidin ortholog from ducks and named dCATH. The cDNA sequence of dCATH encodes a predicted 146-amino-acid polypeptide composed of a 17-residue signal peptide, a 109-residue conserved cathelin domain and a 20-residue mature peptide. Phylogenetic analysis demonstrated that dCATH is highly divergent from other avian peptides. The α-helical structure of the peptide exerted strong antimicrobial activity against a broad range of bacteria in vitro, with most minimum inhibitory concentrations in the range of 2 to 4 μM. Moreover, dCATH also showed cytotoxicity, lysing 50% of mammalian erythrocytes in the presence or absence of 10% fetal calf serum at concentrations of 32 μM or 20 μM and killing 50% HaCaT cells at a concentration of 10 μM. The effects on bacterial outer and inner membranes, as examined by scanning electron microscope and transmission electron microscopy, indicate that dCATH kills microbial cells by increasing permeability, causing a loss of membrane integrity.

Cholesterol-directed nanoparticle assemblies based on single amino acid peptide mutations activate cellular uptake and decrease tumor volume

“…The CD spectra were then converted to mean residue ellipticity using the following equation: 24 [ θ ] obs = [ θ ] 222 × 1000/ cln where [ θ ] obs is mean residue ellipticity [deg cm 2 dmol –1 ], [ θ ] 222 is the observed ellipticity corrected for the buffer at a given wavelength of 222 nm [mdeg], c is the peptide concentration [mM], l is the path length [mm] and n is the number of amino acids.…”

Pseudonajide peptide derived from snake venom alters cell envelope integrity interfering on biofilm formation in Staphylococcus epidermidis

“…Cathelicidin-related antimicrobial peptides (CRAMPs) from snake venoms (specially from Elapidae and Viperidae families) have been studied as models for the design of new antimicrobial pharmaceuticals against bacterial infections, facilitated by complete genome sequences available (7). These bioactive molecules are structurally characterized by an N-terminal segment with a gene-encoded signal peptide and a cathelin domain derived from the cathepsin L-inhibitor (pro-peptide), followed by a C-terminal antimicrobial domain with diverse structures (mature peptide) (8). Venom cDNA libraries from Naja atra, Bothrops atrox, Crotalus durissus terri cus, Pseudonaja textilis, Ophiophagus hannah, and Bungarus fasciatus snake species have revealed different types of cathelicidins (NA-CATH, batroxicidin, crotalicidin, Pt_CRAMP1, OH-CATH, OH-CATH30, cathelicicin-BF) with remarkable antimicrobial activity against Grampositive and -negative bacteria, as well as fungi (1,9,10).…”

Structure and mode of action of a novel antibacterial peptide from the blood of Andrias davidianus

“…Thus, there is an increasing need for better treatments. In recent years, researchers have increasingly turned towards the study of plants and animals in hopes of identifying and characterizing new antimicrobial peptides (AMPs) which have broad‐spectrum antimicrobial activity and unique membrane‐directed mechanism (Gao et al ; Huang et al ; Lyu et al ).…”