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Quantitative Structure-Activity Relationship, Activity Prediction, and Molecular Dynamics of Non-nucleotide Reverse Transcriptase Inhibitors
Published on: May 9, 2025
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Deciphering letermovir's mode of action and resistance mutation effects
C Gourin1, T Flores2, C Lefèvre1
1Université de Limoges, INSERM, RESINFIT, U1092, 2 rue du Dr Marcland, 87025, Limoges, France.
Antiviral Research
|October 9, 2025
Summary
Letermovir does not disrupt human cytomegalovirus terminase complex interactions. Resistance mutations alter subunit binding, offering insights for new antiviral drug development against HCMV infections.
Area of Science:
- Virology
- Drug Discovery
- Molecular Biology
Background:
- Human cytomegalovirus (HCMV) causes severe disease in immunocompromised individuals and is a global health concern.
- The HCMV terminase complex (pUL56-pUL89-pUL51) is a crucial target for antiviral therapies.
- Letermovir inhibits HCMV DNA packaging but its precise mechanism and resistance pathways are not fully understood.
Purpose of the Study:
- To investigate the effect of letermovir on interactions between HCMV terminase subunits.
- To analyze how resistance-associated mutations influence these protein-protein interactions.
- To provide insights into letermovir's mechanism of action and HCMV resistance.
Main Methods:
- Cloning of wild-type and mutant HCMV terminase subunits (pUL56, pUL51) into NanoBiT® PPI and pCI-neo vectors.
- Transfection into HEK293T cells and assessment of protein-protein interactions in the presence or absence of letermovir.
- Utilizing AlphaFold3 and cryo-EM structural analysis to evaluate mutation sites.
Main Results:
- Letermovir did not disrupt interactions between wild-type terminase subunits.
- Resistance mutations significantly modulated the strength of subunit interactions, with some showing synergistic effects in double mutants.
- Structural analysis indicated resistance mutations are located outside the core complex.
Conclusions:
- Letermovir likely does not inhibit HCMV by directly disrupting terminase subunit interactions.
- Understanding resistance mutations provides crucial information for developing novel HCMV antivirals targeting the terminase complex.
- Further research into HCMV resistance mechanisms can guide future therapeutic strategies.
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