Identification of a Permissive Secondary Mutation That Restores the Enzymatic Activity of Oseltamivir Resistance Mutation H275Y

UMMS Affiliation

Department of Biochemistry and Molecular Biotechnology; Department of Medicine; Department of Microbiology and Physiological Systems; Graduate School of Biomedical Sciences; Schiffer Lab

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Biochemistry, Biophysics, and Structural Biology | Enzymes and Coenzymes | Medicinal Chemistry and Pharmaceutics | Medicinal-Pharmaceutical Chemistry | Virology | Viruses


Many oseltamivir resistance mutations exhibit fitness defects in the absence of drug pressure that hinders their propagation in hosts. Secondary permissive mutations can rescue fitness defects and facilitate the segregation of resistance mutations in viral populations. Previous studies have identified a panel of permissive or compensatory mutations in neuraminidase (NA) that restore the growth defect of the predominant oseltamivir resistance mutation (H275Y) in H1N1 influenza A virus. In prior work, we identified a hyperactive mutation (Y276F) that increased NA activity by approximately 70%. While Y276F had not been previously identified as a permissive mutation, we hypothesized that Y276F may counteract the defects caused by H275Y by buffering its reduced NA expression and enzyme activity. In this study, we measured the relative fitness, NA activity, and surface expression, as well as sensitivity to oseltamivir, for several oseltamivir resistance mutations, including H275Y in the wild-type and Y276F genetic background. Our results demonstrate that Y276F selectively rescues the fitness defect of H275Y by restoring its NA surface expression and enzymatic activity, elucidating the local compensatory structural impacts of Y276F on the adjacent H275Y.

IMPORTANCE The potential for influenza A virus (IAV) to cause pandemics makes understanding evolutionary mechanisms that impact drug resistance critical for developing surveillance and treatment strategies. Oseltamivir is the most widely used therapeutic strategy to treat IAV infections, but mutations in IAV can lead to drug resistance. The main oseltamivir resistance mutation, H275Y, occurs in the neuraminidase (NA) protein of IAV and reduces drug binding as well as NA function. Here, we identified a new helper mutation, Y276F, that can rescue the functional defects of H275Y and contribute to the evolution of drug resistance in IAV.


H275Y, Y276F, influenza A virus, neuraminidase

DOI of Published Version



Jiang L, Samant N, Liu P, Somasundaran M, Jensen JD, Marasco WA, Kowalik TF, Schiffer CA, Finberg RW, Wang JP, Bolon DNA. Identification of a Permissive Secondary Mutation That Restores the Enzymatic Activity of Oseltamivir Resistance Mutation H275Y. J Virol. 2022 Mar 23;96(6):e0198221. doi: 10.1128/jvi.01982-21. Epub 2022 Jan 19. PMID: 35045267; PMCID: PMC8941911. Link to article on publisher's site

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Journal of virology

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