Molecular Characterization and Phylogenetic Analysis of Novel Isoform of Anti-lipopolysaccharide Factor from the Mantis Shrimp, Miyakea nepa

Abstract

Anti-lipopolysaccharide factor (ALF) is a cationic anti-microbial peptide representing humoral defence system exhibiting a diverse spectrum of activity against microbial pathogens, including gram-negative and gram-positive bacteria, fungi, parasites and viruses. In this study, we identified and characterized a novel ALF homologue (MnALF) encoding cDNA sequence from the haemocytes of stomatopod mantis shrimp Miyakea nepa. The deduced peptide of MnALF encoded for a 123-amino acid peptide with a 25-residue signal peptide containing selenocysteine followed by a highly cationic mature peptide comprised of a putative LPS-binding domain flanked by two cysteine residues. BLAST analysis of MnALF showed that it exhibits identity to crustacean and limulid ALFs. The mature peptide of MnALF has a net charge of +7 and predicted molecular weight of 10.998 kDa with a theoretical isoelectric point (pI) of 9.93. Spatial structure of MnALF comprises three α-helices packed against a four-stranded β-sheet of which two were linked by a disulphide bond to form an amphipathic loop similar to the structure of Penaeus monodon, ALF-Pm3. All these features suggest that MnALF could play an imperative role in the innate defence mechanism of M. nepa. To our knowledge, this study accounts for the first report of an anti-microbial peptide from the order stomatopoda.

Marine Arthropods as a Source of Antimicrobial Peptides

“…ALFs are by far the most widely studied AMPs in crustaceans, in part because more than 300 peptides of this class have been isolated and characterized so far. Unlike penaeidins, which are found solely in the penaeidae family, ALFs are present in crustaceans and limulids [ 144 ] ( Table 4 ). The first ALF was isolated from the hemolymphs of the chelicerate horseshoe crabs Limulus polyphemus [ 145 ] and Tachypleus tridentatus [ 146 ].…”

Shedding Light on the Antimicrobial Peptide Arsenal of Terrestrial Isopods: Focus on Armadillidins, a New Crustacean AMP Family

“…Indeed, Decapoda ALF sequences are characterized by a large mature peptide (11 kDa) containing a highly hydrophobic N-terminal region and two cysteine residues [2,[14][15][16]. All ALFs sequences belong to the DUF3254 superfamily, characterized by the presence of the DUF3254 protein domain [17,18]. All crustin precursors have a leader sequence at the N-terminal region and a mature multi-domain cationic AMP (7-14 kDa) characterized by the always present WAP (whey acidic protein) domain at the C-terminus [2,14,15,19,20].…”