%0 Journal Article
%T Molecular Characterization and Phylogenetic Analysis of a Histone-Derived Antimicrobial Peptide Teleostin from the Marine Teleost Fishes, Tachysurus jella and Cynoglossus semifasciatus
%A E. R. Chaithanya
%A Rosamma Philip
%A Naveen Sathyan
%A P. R. Anil Kumar
%J ISRN Molecular Biology
%D 2013
%R 10.1155/2013/185807
%X Antimicrobial peptides (AMPs) are host defense peptides that are well conserved throughout the course of evolution. Histones are classical DNA-binding proteins, rich in cationic amino acids, and recently appreciated as precursors for various histone-derived AMPs. The present study deals with identification of the potential antimicrobial peptide sequence of teleostin from the histone H2A of marine teleost fishes, Cynoglossus semifasciatus and Tachysurus jella. A 245£¿bp amplicon coding for 81 amino acids was obtained from the cDNA transcripts of these fishes. The first 52 amino acids from the N terminal of the peptide were identical to previously characterized histone-derived antimicrobial peptides. Molecular and physicochemical characterizations of the sequence were found to be in agreement with previously reported histone H2A-derived AMPs, suggesting the possible role of histone H2A in innate defense mechanism in fishes. 1. Introduction Antimicrobial peptides (AMPs) have made their mark as an emerging class of natural antibiotics [1]. They represent molecules that have been retained by organisms throughout the course of their evolution as a part of defense mechanism against microbial enemies. Generally these gene-encoded ribosomally synthesized small peptides (<10£¿kDa) are cationic and very often amphiphilic moieties with selective broad spectrum antimicrobial activity [2]. The net positive charge enables these peptides to selectively attack negatively charged bacterial cell membranes and bring about destruction of the organism by pore formation or destabilization of membrane equilibrium or by penetration into the cell and thereby the impairment of cellular machinery [3]. This unique relatively irresistible mode of action and specific broad spectrum lytic activity to prokaryotes and virtual nontoxicity towards mammalian cells other than transformed cells make them attractive candidates as novel therapeutic agents [4, 5]. Aquatic organisms live in a microbe dominated environment where their protection from the austere external environment is enabled mainly by the mucosal barrier produced by the underlying epithelial cells [6, 7]. Fish mucus is known to contain a number of nonspecific humoral innate immune parameters including antimicrobial peptides [8¨C10]. Histone-derived antimicrobial peptides (HDAPs) and pleurocidins form two major groups of AMPs reported from fish mucus [9, 10]. Although the role of histone proteins as integral part of eukaryotic chromatin organization and as regulators of transcription is well known, their role in host immune
%U http://www.hindawi.com/journals/isrn.molecular.biology/2013/185807/