Structure-function relationship of antimicrobial peptide cathelicidin Pc-CATH1

Li Dong,Ying Wang,Li-Xian Mu,Dong-Hai Lin,Huan Liu,Ren Lai,Juan-Juan Yang

doi:10.1007/s13659-012-0016-1

Abstract

Cathelicidin Pc-CATH1 is a cathelicidin-derived myeloid antimicrobial peptide identified from Phasianus colchicus with strong antimicrobial activity against most of bacteria and fungi tested, including the clinically isolated (IS) drug-resistant strains. Considering the uniform distribution of net positive charge in both C- and N-terminus sequence of cathelicidin Pc-CATH1 and most of hydrophobic amino acid (aa) residues positioned in middle of the sequence, the antimicrobial peptide was used to investigate the structure-function relationship by truncating gradually N- or C-terminus amino acid residue. More than 10 modified peptide homologues (20–26 aa length) of cathelicidin Pc-CATH1 were found to keep strong antimicrobial abilities. The possible relationships between bioactivities including antimicrobial and hemolytic abilities, components of secondary structure, hydrophobicity, amphipathicity, net charge, and sequence length were investigated. The current work provided suggestions for structural and functional modification of linear, α-helical antimicrobial peptides containing no disulfided bridges.

Highlights

Antimicrobial peptides are important components of the innate immunity system, which is the first line of host defense protecting living organisms from microorganism attacking
Based on the amino acid sequence and secondary structure, they are classified into several groups
Cathelicidin is synthesized as pre-pro-protein containing a N-terminal signal domain, a highly conserved cathelin domain, and the varible C-terminal peptide[3]

Summary

Introduction

Antimicrobial peptides are important components of the innate immunity system, which is the first line of host defense protecting living organisms from microorganism attacking. The antimicrobial activities of cathelicidin Pc-CATH1 and its 29 homologues against a representative set of bacterial and fungi strains, including S. aureus, B. subtilis, E. coli, and C. Nine peptides including LR1–4 and RL1–5 showed strong antimicrobial activities. LR5 showed antimicrobial abilities against three tested microorganism strains including S. aureus, E. coli, and C. albicans but B. subtilis.

Results

Conclusion