The role of conserved QXG and binding affinity of S23G & S26G receptors on avian H5, swine H1 and human H1 of influenza A virus hemagglutinin.

Outbreaks of avian, human and swine influenza are a serious concern for public health. In the reproductive cycle of the influenza virus, hemagglutinin (HA) is the primary protein responsible for binding to glycan receptor sites on the host cell surface. MD simulations of avian H5, swine H1 and human H1 complexed with S23G and S26G receptors were performed to study the role of key residues on the receptor conformational behaviors, hydrogen bond formation, binding free energy and residue-wise energy contribution. The obtained results indicated that the relative energies of swH1_S23G and swH1_S26G were found to be close to each other (3.1 kcal/mol) while the relative energies of AvH5 and HuH1 were found to be significantly different (11.1 ± 6.8 and 29.0 ± 8.2 kcal/mol for AvH5 and HuH1, respectively).