Inactivation of influenza virus haemagglutinin by chlorine dioxide: oxidation of the conserved tryptophan 153 residue in the receptor-binding site

Norio Ogata

doi:10.1099/vir.0.044263-0

Abstract

Airborne influenza virus infection of mice can be prevented by gaseous chlorine dioxide (ClO(2)). This study demonstrated that ClO(2) abolished the function of the haemagglutinin (HA) of influenza A virus (H1N1) in a concentration-, time- and temperature-dependent manner. The IC(50) during a 2 min reaction with ClO(2) at 25 °C was 13.7 µM, and the half-life time of HA with 100 µM ClO(2) at 25 °C was 19.5 s. Peptides generated from a tryptic digest of ClO(2)-treated virus were analysed by mass spectrometry. An HA fragment, (150)NLLWLTGK(157) was identified in which the tryptophan residue (W153) was 32 mass units greater than expected. The W153 residue of this peptide, which is derived from the central region of the receptor-binding site of HA, is highly conserved. It was shown that W153 was oxidized to N-formylkynurenine in ClO(2)-treated virus. It was concluded that the inactivation of influenza virus by ClO(2) is caused by oxidation of W153 in HA, thereby abolishing its receptor-binding ability.

Highlights

Influenza virus is an enveloped, negative-sense ssRNA virus with three transmembrane proteins, two of which are known as spike proteins, the haemagglutinin (HA) (Gamblin & Skehel, 2010; Skehel & Wiley, 2000) and neuraminidase (NA) (Xie et al, 2011)
Conserved amino acid residues are present in the receptor-binding site, including Y98, S136, W153, H183, E190 and Y195 (Gamblin & Skehel, 2010; Stevens et al, 2004, 2006)
The results presented in this paper clearly demonstrate that inactivation of influenza virus by ClO2 is due to oxidation and elimination of the function of the HA molecule

Summary

Introduction

Influenza virus is an enveloped, negative-sense ssRNA virus with three transmembrane proteins, two of which are known as spike proteins, the haemagglutinin (HA) (Gamblin & Skehel, 2010; Skehel & Wiley, 2000) and neuraminidase (NA) (Xie et al, 2011). The functions of HA are indispensable for the early establishment of infection in a target cell (Skehel & Wiley, 2000). An HA receptor on the target cell binds to a receptor-binding site of HA. Conserved amino acid residues are present in the receptor-binding site, including Y98, S136, W153, H183, E190 and Y195 (Gamblin & Skehel, 2010; Stevens et al, 2004, 2006) Among these conserved residues, W153 is located at the bottom of the binding site just below the acetamide moiety of the sialic acid (Nacetylneuraminic acid) residue of the receptor (Lin et al, 2009)

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Results

Conclusion