Influenza virus causes severe respiratory infection in humans. Current antivirotics target three key proteins in the viral life cycle: neuraminidase, the M2 channel and the endonuclease domain of RNA-dependent-RNA polymerase. Due to the development of novel pandemic strains, additional antiviral drugs targetting different viral proteins are still needed. The protein-protein interaction between polymerase subunits PA and PB1 is one such possible target. We recently identified a modified decapeptide derived from the N-terminus of the PB1 subunit with high affinity for the C-terminal part of the PA subunit. Here, we optimized its amino acid hotspots to maintain the inhibitory potency and greatly increase peptide solubility. This allowed thermodynamic characterization of peptide binding to PA. Solving the X-ray structure of the peptide-PA complex provided structural insights into the interaction. Additionally, we optimized intracellular delivery of the peptide using a bicyclic strategy that led to improved inhibition in cell-based assays.
Influenza viruses can cause severe respiratory infections in humans, leading to nearly half a million deaths worldwide each year. Improved antiviral drugs are needed to address the threat of development of novel pandemic strains. Current therapeutic interventions target three key proteins in the viral life cycle: neuraminidase, the M2 channel and RNA-dependent-RNA polymerase. Protein-protein interactions between influenza polymerase subunits are potential new targets for drug development. Using a newly developed assay based on AlphaScreen technology, we screened a peptide panel for protein-protein interaction inhibitors to identify a minimal PB1 subunit-derived peptide that retains high inhibition potential and can be further modified. Here, we present an X-ray structure of the resulting decapeptide bound to the C-terminal domain of PA polymerase subunit from pandemic isolate A/California/07/2009 H1N1 at 1.6 Å resolution and discuss its implications for the design of specific, potent influenza polymerase inhibitors.
- MeSH
- antivirové látky farmakologie MeSH
- interakční proteinové domény a motivy účinky léků fyziologie MeSH
- krystalizace MeSH
- lidé MeSH
- RNA-dependentní RNA-polymerasa chemie metabolismus MeSH
- vazba proteinů MeSH
- virové proteiny antagonisté a inhibitory chemie metabolismus MeSH
- virus chřipky A, podtyp H1N1 účinky léků enzymologie metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Influenza A virus (IAV) encodes a polymerase composed of three subunits: PA, with endonuclease activity, PB1 with polymerase activity and PB2 with host RNA five-prime cap binding site. Their cooperation and stepwise activation include a process called cap-snatching, which is a crucial step in the IAV life cycle. Reproduction of IAV can be blocked by disrupting the interaction between the PB2 domain and the five-prime cap. An inhibitor of this interaction called pimodivir (VX-787) recently entered the third phase of clinical trial; however, several mutations in PB2 that cause resistance to pimodivir were observed. First major mutation, F404Y, causing resistance was identified during preclinical testing, next the mutation M431I was identified in patients during the second phase of clinical trials. The mutation H357N was identified during testing of IAV strains at Centers for Disease Control and Prevention. We set out to provide a structural and thermodynamic analysis of the interactions between cap-binding domain of PB2 wild-type and PB2 variants bearing these mutations and pimodivir. Here we present four crystal structures of PB2-WT, PB2-F404Y, PB2-M431I and PB2-H357N in complex with pimodivir. We have thermodynamically analysed all PB2 variants and proposed the effect of these mutations on thermodynamic parameters of these interactions and pimodivir resistance development. These data will contribute to understanding the effect of these missense mutations to the resistance development and help to design next generation inhibitors.
- MeSH
- krystalografie rentgenová MeSH
- kvantová teorie MeSH
- molekulární modely MeSH
- mutace genetika MeSH
- mutantní proteiny metabolismus MeSH
- podjednotky proteinů antagonisté a inhibitory chemie metabolismus MeSH
- proteinové domény MeSH
- pyridiny chemie farmakologie MeSH
- pyrimidiny chemie farmakologie MeSH
- pyrroly chemie farmakologie MeSH
- RNA-dependentní RNA-polymerasa antagonisté a inhibitory chemie metabolismus MeSH
- termodynamika MeSH
- virová léková rezistence účinky léků MeSH
- virové proteiny antagonisté a inhibitory chemie metabolismus MeSH
- virus chřipky A účinky léků enzymologie MeSH
- Publikační typ
- časopisecké články MeSH
