A Novel Isoform of the Hepatic Antimicrobial Peptide, Hepcidin (Hepc-CB1), from a Deep-Sea Fish, the Spinyjaw Greeneye Chlorophthalmus bicornis (Norman, 1939): Molecular Characterisation and Phylogeny

Abstract

Hepcidin is cysteine-rich short peptide of innate immune system of fishes, equipped to perform prevention and proliferation of invading pathogens like bacteria and viruses by limiting iron availability and activating intracellular cascades. Hepcidins are diverse in teleost fishes, due to the varied aquatic environments including exposure to pathogens, oxygenation and iron concentration. In the present study, we report a 87-amino acid (aa) preprohepcidin (Hepc-CB1) with a signal peptide of 24 aa, a prodomain of 39 aa and a bioactive mature peptide of 24 aa from the gill mRNA transcripts of the deep-sea fish spinyjaw greeneye, Chlorophthalmus bicornis. Molecular characterisation and phylogenetic analysis categorised the peptide to HAMP2-like group with a mature peptide of 2.53 kDa; a net positive charge (?3) and capacity to form b-hairpin-like structure configured by 8 conserved cysteines. The present work provides new insight into the mass gene duplication events and adaptive evolution of hepcidin isoforms with respect to environmental influences and positive Darwinian selection. This work reports a novel hepcidin isoform under the group HAMP2 from a nonacanthopterygian deep-sea fish, C. bicornis.

Hepcidin: Homeostasis and Diseases Related to Iron Metabolism

“…In humans, this isoform is involved in iron metabolism, similar to an active molecule containing 25 amino acids [23,24]. …”

A hepatic antimicrobial peptide, hepcidin from Indian major carp, Catla catla: molecular identification and functional characterization

“…Fish hepcidins are categorized into two, HAMP1 and HAMP2 based on amino acid sequence, cationicity, and the iron binding motif DTHFP or QSHLS. HAMP1 hepcidins has similarity with mammalian hepcidins whereas HAMP2 present only in acanthopterygians except Chlorophthalmus bicornis [ 19 ]. Diversification and duplication of gene resulted in the formation of multiple copies of hepcidin in the genome, identified up to 8 copies [ 23 , 58 , 73 ].…”