Identification and in silico structural and functional analysis of a histone H2A-derived antimicrobial peptide from teleost fishes

Abstract

BackgroundAntimicrobial peptides (AMPs) are small peptides that form the first line of defence in all living organisms. In addition to conventional AMPs, there exist molecules that are often not regarded as part of the innate defences, but possess antimicrobial activity. Histone H2A-derived peptides are a group of unconventional AMPs that represent very ancient defence factors, re-used in new ways during evolution. The present study attempts to compare histone H2A-derived AMPs from four commercially important teleost fishes inhabiting various habitats, viz. Asian sea bass (Lates calcarifer), tank goby (Glossogobius giuris), grey mullet (Mugil cephalus), and Malabar trevally (Carangoides malabaricus). Methods and resultsRT-PCR amplification of the mRNAs extracted from these fishes yielded H2A-derived AMP genes with slight differences in the nucleotide sequences, nevertheless with similar translated amino acid sequences. The amino acid sequence was found to possess marked similarity at the N-terminal region and showed antimicrobial motif sequence characteristic of histone H2A-derived AMPs. Phylogenetic analysis showed an evolutionary relationship with invertebrate ones suggesting a common ancestral origin for the vertebrate and invertebrate histone H2A. The secondary structure of histone H2A-derived AMP showed the presence of α-helices and intermittent coils having a proline hinge connecting the N- and C-terminus. The peptide was also predicted to be a cell-penetrating one. ConclusionIn silico structural and functional characterization of histone H2A-derived AMP revealed its potential antibacterial property and point towards the possibility of being an efficient AMP with the potential of being made use of in therapeutics.