Identification of a Novel Antifungal Peptide with Chitin-Binding Property from Marine Metagenome

Muthuirulan      Pushpanathan; Jeyaprakash      Rajendhran; Sathyanarayanan      Jayashree; Balakrishnan      Sundarakrishnan; Seetharaman      Jayachandran; Paramasamy      Gunasekaran

doi:10.2174/092986612803521620

Abstract

A novel antifungal peptide with 36 amino acids was identified by functional screening of a marine metagenomic library. The peptide did not show similarity with any existing antimicrobial peptide sequences in the databank. The108 bp ORF designated as mmgp1 was cloned and expressed in Escherichia coli BL21 (DE3) using pET expression system. Mass spectrometry analysis of the purified recombinant peptide revealed a molecular mass of 5026.9 Da. The purified recombinant peptide inhibited the growth of Candida albicans and Aspergillus niger. The peptide was predicted to adopt α- helical conformation with an extended coil containing a ligand binding site for N-acetyl-D-glucosamine. The α- helicity of the peptide was demonstrated by circular dichroism spectroscopy in the presence of chitin or membrane mimicking solvent, trifluoroethanol. The chitin binding property of the peptide was also confirmed by fast performance liquid chromatography.

Keywords: Marine metagenome, gene expression, purification, antifungal peptide, fungal infections, systemic fungal, infections, human pathology, therapeutic agents, gene clusters, DNA.