tetano
Editor, Senior Moderator
Arch Biochem Biophys
. 2024 May 13:110041.
doi: 10.1016/j.abb.2024.110041. Online ahead of print. Structural and functional characterization of avian influenza H9N2 virus neuraminidase with a combination of five novel mutations
Deeksha S Tare[SUP] 1 [/SUP], Shailesh D Pawar[SUP] 2 [/SUP], Pratip Shil[SUP] 1 [/SUP], Nitin M Atre[SUP] 1 [/SUP]
Affiliations
The influenza virus neuraminidase (NA) protein is responsible for actively cleaving the sialic acid (SA) bound to the viral hemagglutinin. In the present study we identified a combination of five novel amino acid substitutions in the NA, conferring increased substrate binding and altered surface characteristics to a low pathogenic avian influenza (LPAI) H9N2 strain. The H9N2 virus strain reported from India, namely, A/Environmental/India/1726265/2017 (H9N2-1726265) showed the combination of amino acid substitutions T149I, R249W, G346A, W403R and G435R, which were in the vicinity of the enzyme active site cavity. The strain A/chicken/India/99321/2009 (H9N2-99321) did not show these substitutions and was used for comparison. Virus elution was studied using turkey red blood cells (tRBCs). NA enzyme kinetics assays were carried out using the MUNANA substrate, which is a SA analogue. Homology modelling and molecular docking were performed to determine alterations in the surface characteristics and substrate binding. H9N2-1726265 showed enhanced elution from turkey red blood cells. Enzyme kinetics revealed a lower K[SUB]M[/SUB] of H9N2-1726265 (111.5 μM) as compared to H9N2-99321 (135.2 μM), indicating higher substrate binding affinity of H9N2-1726265 due to which the NA enzyme cleaved the SA more efficiently, leading to faster elution. Molecular docking revealed a greater number of binding interactions of H9N2-1726265 to SA as compared to H9N2-99321 which explained the greater substrate binding affinity. Changes in the surface charge, hydrophobicity, and contour, were observed in H9N2-1726265 NA due to the substitutions. Thus, the novel combination of five amino acids near the sialic acid binding site of NA, resulted in altered surface characteristics, higher substrate binding affinity and virus elution.
Keywords: Avian influenza H9N2; enzyme kinetics; molecular docking; neuraminidase; virus elution.
. 2024 May 13:110041.
doi: 10.1016/j.abb.2024.110041. Online ahead of print. Structural and functional characterization of avian influenza H9N2 virus neuraminidase with a combination of five novel mutations
Deeksha S Tare[SUP] 1 [/SUP], Shailesh D Pawar[SUP] 2 [/SUP], Pratip Shil[SUP] 1 [/SUP], Nitin M Atre[SUP] 1 [/SUP]
Affiliations
- PMID: 38750923
- DOI: 10.1016/j.abb.2024.110041
The influenza virus neuraminidase (NA) protein is responsible for actively cleaving the sialic acid (SA) bound to the viral hemagglutinin. In the present study we identified a combination of five novel amino acid substitutions in the NA, conferring increased substrate binding and altered surface characteristics to a low pathogenic avian influenza (LPAI) H9N2 strain. The H9N2 virus strain reported from India, namely, A/Environmental/India/1726265/2017 (H9N2-1726265) showed the combination of amino acid substitutions T149I, R249W, G346A, W403R and G435R, which were in the vicinity of the enzyme active site cavity. The strain A/chicken/India/99321/2009 (H9N2-99321) did not show these substitutions and was used for comparison. Virus elution was studied using turkey red blood cells (tRBCs). NA enzyme kinetics assays were carried out using the MUNANA substrate, which is a SA analogue. Homology modelling and molecular docking were performed to determine alterations in the surface characteristics and substrate binding. H9N2-1726265 showed enhanced elution from turkey red blood cells. Enzyme kinetics revealed a lower K[SUB]M[/SUB] of H9N2-1726265 (111.5 μM) as compared to H9N2-99321 (135.2 μM), indicating higher substrate binding affinity of H9N2-1726265 due to which the NA enzyme cleaved the SA more efficiently, leading to faster elution. Molecular docking revealed a greater number of binding interactions of H9N2-1726265 to SA as compared to H9N2-99321 which explained the greater substrate binding affinity. Changes in the surface charge, hydrophobicity, and contour, were observed in H9N2-1726265 NA due to the substitutions. Thus, the novel combination of five amino acids near the sialic acid binding site of NA, resulted in altered surface characteristics, higher substrate binding affinity and virus elution.
Keywords: Avian influenza H9N2; enzyme kinetics; molecular docking; neuraminidase; virus elution.