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

Wei Gao,Na Yang,Pei Qu,Huixian Chen,Xingjun Feng,Tingting Tan,Dan Li,Liwei Xing

doi:10.1038/srep17260

Wei Gao, Na Yang + Show 6 more

Open Access

https://doi.org/10.1038/srep17260

Copy DOI

Journal: Scientific Reports	Publication Date: Nov 26, 2015
Citations: 41	License type: CC BY 4.0

Affiliation: Northeast Agricultural University

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.

Highlights

The family of antimicrobial peptide, cathelicidins, which plays important roles against infections in animals, has been identified from many species
The 441-bp cDNA and the deduced 146-amino-acid sequence from the cDNA sequence are shown in Fig. 1, which has been deposited in GenBank (GenBank accession number: KT230679)
Antimicrobial peptides (AMPs) have attracted a great deal of attention as alternative antibiotic candidates because of their broad spectrum of activity against Gram-positive and Gram-negative bacteria, enveloped viruses including HIV, and fungi such as Candida and Cryptococcus[19,20]

Summary

Introduction

The family of antimicrobial peptide, cathelicidins, which plays important roles against infections in animals, has been identified from many species. Cathelicidins are a major family of AMPs newly identified in vertebrate animals[3] This series of peptides typically contain a conserved N-terminal sequence (“cathelin” domain) and a C-terminal antimicrobial domain of varied sequence and length that is a highly diversified and biologically active mature sequence[4]. Most cathelicidins are proteolytically cleaved to release the cathelin domain and C-terminal mature peptides with antimicrobial activities[6] In addition to their primary antimicrobial activities against bacteria, fungi, and enveloped viruses, mature cathelicidins play vital roles in various phases of the host immune system, such as induction of angiogenesis; promotion of wound healing; chemotaxis of neutrophils, monocytes, mast cells and T cells; and inhibition of apoptosis[6]. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to directly observe changes in cell morphology as a result of peptide treatment

Methods

Results

Conclusion