Phylogenetic and In Silico Analysis of Niemann-pick type C1 (NPC1) Transporter Required for Ebola Viral Entry

Ebola virus (EBOV) has recently emerged as a highly virulent organism of concern to humans. The pathology behind the hemorrhagic fever within an EBOV host remains largely unclear, and demands rather novel therapeutics to effectively eradicate this virus. The Niemann-pick type C1 (NPC1) protein cholesterol transporter is required for EBOV entry and internalization into a mammalian host cell. On this premise, an organism’s NPC1 can decide the virus-species specificity. Here, the phylogenetic relationships among twelve selected chordates were examined to determine their predicted ligand binding site (LBS). LBS delineates the functional glycosylated part of the NPC1 transporter and mediates in molecular processes. The 13-helix transmembrane of NPC1 and its sub-domains were also assessed, alongside potential sites of direct interaction with the Ebola glycoprotein. The study revealed that eight functional glycosylated residues: Y420, Q421, Y423, P424, S425, G426, D428 and N452 in the human NPC1 domain C (NPC1-C) surface can form protein complexes with EBOV cleaved glycoprotein (GPcl). Mutation analysis of the NPC1-C in these chordates also revealed multiple deletions and insertions in snakes, but single amino acid changes in the bat, rat and carnivore species. The mutation attributes of the chordates can remarkably contribute to their refractory capacity to EBOV infection. More studies on the orthologs of NPC1 are required to delineate the key sequences that aid or inhibit how susceptible organisms are to Ebola virus infection.