Characterization of Histone H2A Derived Antimicrobial Peptides, Harriottins, from Sicklefin Chimaera Neoharriotta pinnata (Schnakenbeck, 1931) and Its Evolutionary Divergence with respect to CO1 and Histone H2A.

Naveen Sathyan,E R Chaithanya,I S Bright Singh,V N Sanjeevan,Rosamma Philip,P R Anil Kumar

doi:10.1155/2013/930216

Naveen Sathyan, E R Chaithanya + Show 4 more

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https://doi.org/10.1155/2013/930216

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Abstract

Antimicrobial peptides (AMPs) are humoral innate immune components of fishes that provide protection against pathogenic infections. Histone derived antimicrobial peptides are reported to actively participate in the immune defenses of fishes. Present study deals with identification of putative antimicrobial sequences from the histone H2A of sicklefin chimaera, Neoharriotta pinnata. A 52 amino acid residue termed Harriottin-1, a 40 amino acid Harriottin-2, and a 21 mer Harriottin-3 were identified to possess antimicrobial sequence motif. Physicochemical properties and molecular structure of Harriottins are in agreement with the characteristic features of antimicrobial peptides, indicating its potential role in innate immunity of sicklefin chimaera. The histone H2A sequence of sicklefin chimera was found to differ from previously reported histone H2A sequences. Phylogenetic analysis based on histone H2A and cytochrome oxidase subunit-1 (CO1) gene revealed N. pinnata to occupy an intermediate position with respect to invertebrates and vertebrates.

Highlights

Antimicrobial peptides (AMPs) are ubiquitous and multipotent components of humoral innate immune response of most living organisms against invasion by pathogens [1]
N-terminus of histone H2A is rich in basic amino acids, a characteristic which allows histone H2A to act as a precursor for antimicrobial peptides [7]
Basic Local Alignment Search Tool (BLAST) analysis of nucleotide sequences confirmed the identity of the organism as N. pinnata showing 99% similarity to GenBank ID: HM239670.1 Neoharriotta pinnata

Summary

Introduction

Antimicrobial peptides (AMPs) are ubiquitous and multipotent components of humoral innate immune response of most living organisms against invasion by pathogens [1]. The characteristics of naturally occurring AMPs, such as relatively small size (12–50 amino acids), cationicity, and amphipathicity allow them to interact with and penetrate into the membranes by the formation of transmembrane ion permeable pores or by a detergent-like manner, resulting in the leakage of the cytoplasmic components and cell death [2]. In the last two decades a considerable number of gene coded AMPs, either inducible or constitutive, with broad spectrum activity against different types of pathogens, have been reported from wide range of organisms, and their significance in innate immunity is becoming more and more appreciated. In case of marine fishes AMPs derived from the Nterminus domain of histone H2A have been reported from

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