A Combined NMR-Computational Study of the Interaction between Influenza Virus Hemagglutinin and Sialic Derivatives from Human and Avian Receptors on the Surface of Transfected Cells.

Donatella Potenza,Antonio Siccardi,Guido Tiana,Francesca Vasile,Maddalena Panigada

doi:10.3390/ijms19051267

Abstract

The development of small-molecule inhibitors of influenza virus Hemagglutinin could be relevant to the opposition of the diffusion of new pandemic viruses. In this work, we made use of Nuclear Magnetic Resonance (NMR) spectroscopy to study the interaction between two derivatives of sialic acid, Neu5Ac-α-(2,6)-Gal-β-(1–4)-GlcNAc and Neu5Ac-α-(2,3)-Gal-β-(1–4)-GlcNAc, and hemagglutinin directly expressed on the surface of recombinant human cells. We analyzed the interaction of these trisaccharides with 293T cells transfected with the H5 and H1 variants of hemagglutinin, which thus retain their native trimeric conformation in such a realistic environment. By exploiting the magnetization transfer between the protein and the ligand, we obtained evidence of the binding event, and identified the epitope. We analyzed the conformational features of the glycans with an approach combining NMR spectroscopy and data-driven molecular dynamics simulations, thus obtaining useful information for an efficient drug design.

Highlights

Influenza viruses are important respiratory pathogens that have caused significant morbidity, mortality, and considerable economic losses in the recurrent yearly epidemics
The fight against the spread of the influenza virus requires an effort to understand the molecular mechanism that favors the diffusion of the virus, and we can benefit from this understanding in order to develop new antiviral small molecules
Since vaccines can be compromised by the rapidity with which the influenza virus mutates, the use of antiviral small molecules represents a valuable alternative

Summary

Introduction

Influenza viruses are important respiratory pathogens that have caused significant morbidity, mortality, and considerable economic losses in the recurrent yearly epidemics. Influenza viruses include several genera, such as A, B and C; only a few serotypes of the influenza A virus (IAV) have caused influenza pandemics in the last 100 years [1]. The influenza virions carry a lipid envelope embedding three surface proteins: hemagglutinin (HA), neuraminidase (NA), and the M2 proton channel protein. Based on the antigenicity of HA and NA, IAV can be further classified into different subtypes, including 16 HA (H1–H16) and 9 NA (N1–N9) subtypes. HA triggers the internalization into the host cell, upon binding with the sialic-acid-containing glycans on the host membrane. The role of NA is to release the newly formed virus particles from an infected cell

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