Schematic representation mapping of positively selected sites and tertiary structure models for both ISAV surface proteins. (A) Structural model of the HE protein from ISAV by homology with the HEF protein from influenza C virus (PDB ID 1FLC) with V134 and S340 residues in Van der Waals representation. (B) Alignment of secondary structural prediction (using PSIPRED) for sequence and model of ISAV HE against HEF protein. The alpha helix structural prediction is shown as red cylinders and Beta strands in yellow arrow representation. (C) Structural model of the Fusion protein from ISAV 901 (without insertion) by homology with HEF protein from influenza C virus (PDB ID 1FLC) and HE from Influenza A virus (PDB ID 3EYJ). (D) Superposition of models of the ISAV fusion protein with and without different insertions. (E) Zoomed image of alpha helix, which contains putative fusion peptides and different insertions with A279 residue in Van der Waals representation. (F) Alignment of secondary structural prediction (using PSIPRED) for different sequences and models of ISAV Fusions against HEF protein. The alpha helix structure prediction is shown as red cylinders and Beta strands as yellow arrows. Positively selected sites were deemed as such when the dN/dS rate ratio was greater than 1 and with a p-value less than 0.1. Amino acid numbering according to ISAV752 09 (ADF36500 for Hemagglutinin and ADF36499 for Fusion). Black arrows denote positively selected sites. Blue labels indicate landmarks in the genes, i.e., GS, glycosylation site; IN, insertion; RB, recombination breakpoint; PPPS, putative protease-processing site; HPR, Highly Polymorphic Region; TM, Transmembrane domain.
Castro-Nallar et al. BMC Evolutionary Biology 2011 11:349 doi:10.1186/1471-2148-11-349