Characterization of transcription profile and structural properties of avian NK-lysin

Abstract

This study aimed to determine the transcription profile of NK-lysin gene in native chickens. Moreover, it was targeted toward determining the primary, three-dimensional, and molecular dynamic structures of NK-lysin and granulysin peptides to understand their mode of action and intracellular transduction pathways using in silico analysis. The results revealed that NK-lysin gene in native chickens and Gallus gallus were closely related to those of other avian species. However, there was a low sequence homology when aligned with the mammalian peptides. The coding region of NK-lysin peptide in native chickens encoded 140 amino acids as found in G. gallus with a homology of 98% that declined to 20%, particularly in mammalian species. The results revealed that the NK-lysin in native chickens was closely related to that in avian species at a range of 71–76%. However, it was different from that of other mammalians in terms of nucleotide and amino acid identities. The mRNA transcripts of NK-lysin had high and moderate expression levels in the testis and pancreas, respectively. Nonetheless, the small intestine, kidney, spleen, and liver had a low expression level. The NK-lysin peptides contained more than 50% of the total AA with a nonpolar feature, whereas polar AA constituted up to 30% of AA. The results also indicated that the hydrophilic regions and positively charged amino acids were predominant on the surface of the investigated peptides. The NK-lysin was folded in 4–5 helical units and 3–4 loop structures in their saposin domain. The third helical peptide was long in both avian and bovine species (104–123 residues). However, the fourth helical peptide was short in humans, pigs, and chimpanzees (101–123, 104–123, and 102–124 residues, respectively), with the helical unit residues of 95–97, 96–99, and 96–98, respectively. The obtained results can be helpful in developing novel approaches that could be used as alternatives or adjuncts to the existing means of control.