title: Molecular Characterization of a Newly Identified Subfamily Member of Penaeidin from two Penaeid Shrimps, Fenneropenaeus indicus and Metapenaeus monoceros.
abstract: Penaeidins are a major group of antimicrobial peptides found in penaeid shrimps. This study reports a new isoform of penaeidin from the hemocytes of Indian white shrimp, Fenneropenaeus indicus (Fi-PEN, JX657680), and the pink shrimp, Metapenaeus monoceros (Mm-PEN, KF275674). Mm-PEN is also the first antimicrobial peptide to be identified from M. monoceros. The complete coding sequences of the newly identified Fi-PEN and Mm-PEN consisted of an ORF of 338 bp encoding 71 amino acids with a predicted molecular weight of 5.66 kDa and a pI of 9.38. The penaeidins had its characteristic signal peptide region (19 amino acids), which was followed by a mature peptide with a proline-rich domain (24 amino acids) at the N-terminal region and a cysteine-rich domain (28 amino acids) at the C-terminal region, designating it to penaeidin-3 subgroup. Structural analysis revealed an alpha-helix in its secondary structure and an extended structure at the proline-rich domain. The newly identified penaeidin isoform showed maximum similarity of 63 % to a penaeidin-3 isoform of P. monodon, which further proves it to be a new isoform. Phylogenetic analysis showed that it possessed similar evolutionary status like other penaeidins, which has subsequently diverged at different phases of evolution. The wide distribution of penaeidins in penaeid shrimps indicates the importance of these AMPs in the innate immunity.
authors.affiliation: Department of Marine Biology, Microbiology and Biochemistry, School of Marine Sciences, Cochin University of Science and Technology, Fine Arts Avenue, Kochi, Kerala, 682 016, India.
authors.forename: V V
authors.initials: VV
authors.lastname: Afsal
authors.affiliation: Department of Marine Biology, Microbiology and Biochemistry, School of Marine Sciences, Cochin University of Science and Technology, Fine Arts Avenue, Kochi, Kerala, 682 016, India.|National Centre for Aquatic Animal Health, Cochin University of Science and Technology, Fine Arts Avenue, Kochi, Kerala, 682 016, India.
authors.forename: Swapna P
authors.initials: SP
authors.lastname: Antony
authors.affiliation: Department of Marine Biology, Microbiology and Biochemistry, School of Marine Sciences, Cochin University of Science and Technology, Fine Arts Avenue, Kochi, Kerala, 682 016, India. rosammap@gmail.com.
authors.forename: Rosamma
authors.initials: R
authors.lastname: Philip
authors.affiliation: National Centre for Aquatic Animal Health, Cochin University of Science and Technology, Fine Arts Avenue, Kochi, Kerala, 682 016, India.
authors.forename: I S
authors.initials: IS
authors.lastname: Bright Singh
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000145:classification / Q000302:isolation & purification*; D008958:Models, Molecular; D033561:Penaeidae / Q000737:chemistry*; D010802:Phylogeny; D011487:Protein Conformation; D020033:Protein Isoforms / Q000737:chemistry / Q000145:classification / Q000302:isolation & purification; D016415:Sequence Alignment
chemical_list: D023181:Antimicrobial Cationic Peptides; D020033:Protein Isoforms; C000612440:penaeidin, Fenneropenaeus indicus; C000612441:penaeidin, Metapenaeus monoceros
keywords: Antimicrobial peptide; Fenneropenaeus indicus; Innate immunity; Metapenaeus monoceros; Penaeidin