DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Structural Studies of Inhibitors with Clinically Relevant Influenza Endonuclease Variants

Journal Article · · Biochemistry

Vital to the treatment of influenza is the use of antivirals such as Oseltamivir (Tamiflu) and Zanamivir (Relenza); however, antiviral resistance is becoming an increasing problem for these therapeutics. The RNA-dependent RNA polymerase acidic N-terminal (PAN) endonuclease, a critical component of influenza viral replication machinery, is an antiviral target that was recently validated with the approval of Baloxavir Marboxil (BXM). Despite its clinical success, BXM has demonstrated susceptibility to resistance mutations, specifically the I38T, E23K, and A36 V mutants of PAN. To better understand the effects of these mutations on BXM resistance and improve the design of more robust therapeutics, this study examines key differences in protein–inhibitor interactions with two inhibitors and the I38T, E23K, and A36 V mutants. Differences in inhibitor binding were evaluated by measuring changes in binding to PAN using two biophysical methods. The binding mode of two distinct inhibitors was determined crystallographically with both wild-type and mutant forms of PAN. Collectively, these studies give some insight into the mechanism of antiviral resistance of these mutants.

Research Organization:
Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF)
Grant/Contract Number:
AC02-05CH11231
OSTI ID:
2337821
Journal Information:
Biochemistry, Journal Name: Biochemistry Journal Issue: 3 Vol. 63; ISSN 0006-2960
Publisher:
American Chemical Society (ACS)Copyright Statement
Country of Publication:
United States
Language:
English

References (29)

A Biophysical Toolkit for Molecular Interactions reference-book January 2017
Side-chain conformational entropy in protein folding journal November 1995
Reproducibility and accuracy of microscale thermophoresis in the NanoTemper Monolith: a multi laboratory benchmark study journal April 2021
Influenza and antiviral resistance: an overview journal February 2020
Global update on the susceptibilities of human influenza viruses to neuraminidase inhibitors and the cap-dependent endonuclease inhibitor baloxavir, 2018–2020 journal April 2022
Leveraging hospital big data to monitor flu epidemics journal February 2018
Chemical scaffold recycling: Structure-guided conversion of an HIV integrase inhibitor into a potent influenza virus RNA-dependent RNA polymerase inhibitor designed to minimize resistance potential journal February 2023
Fragment-Based Identification of Influenza Endonuclease Inhibitors journal June 2016
SAR Exploration of Tight-Binding Inhibitors of Influenza Virus PA Endonuclease journal September 2019
Computational Prediction of the Binding Pose of Metal-Binding Pharmacophores journal February 2022
The cap-snatching endonuclease of influenza virus polymerase resides in the PA subunit journal February 2009
Structure of influenza A polymerase bound to the viral RNA promoter journal November 2014
Protein-Structure Assisted Optimization of 4,5-Dihydroxypyrimidine-6-Carboxamide Inhibitors of Influenza Virus Endonuclease journal December 2017
Characterization of influenza virus variants induced by treatment with the endonuclease inhibitor baloxavir marboxil journal June 2018
What does I50 mean? journal November 1983
Protein folding--what's the question? journal January 1993
Influenza A Virus Polymerase: Structural Insights into Replication and Host Adaptation Mechanisms journal September 2010
Treatment-Emergent Influenza Virus Polymerase Acidic Substitutions Independent of Those at I38 Associated With Reduced Baloxavir Susceptibility and Virus Rebound in Trials of Baloxavir Marboxil journal April 2020
Structural insights into the substrate specificity of the endonuclease activity of the influenza virus cap-snatching mechanism journal January 2021
The novel influenza A virus protein PA-X and its naturally deleted variant show different enzymatic properties in comparison to the viral endonuclease PA journal September 2015
Nucleoside Monophosphate Complex Structures of the Endonuclease Domain from the Influenza Virus Polymerase PA Subunit Reveal the Substrate Binding Site inside the Catalytic Center journal July 2009
Identification of the I38T PA Substitution as a Resistance Marker for Next-Generation Influenza Virus Endonuclease Inhibitors journal April 2018
Evaluating the fitness of PA/I38T-substituted influenza A viruses with reduced baloxavir susceptibility in a competitive mixtures ferret model journal May 2021
Influenza A virus polymerase acidic protein E23G/K substitutions weaken key baloxavir drug-binding contacts with minimal impact on replication and transmission journal July 2022
A New Understanding of Protein Mutation Unfolds journal January 2005
Update: Influenza Activity in the United States During the 2018–19 Season and Composition of the 2019–20 Influenza Vaccine journal June 2019
Influenza Activity and Composition of the 2022–23 Influenza Vaccine — United States, 2021–22 Season journal July 2022
Preparing for the Next Influenza Season: Monitoring the Emergence and Spread of Antiviral Resistance journal February 2023
Drug Repurposing for Influenza Virus Polymerase Acidic (PA) Endonuclease Inhibitor journal December 2021