Structural Basis of Second-Generation HIV-1 Maturation Inhibitor Activity by Magic Angle Spinning NMR

Kumar, K.; Zadorozhnyi, R.; Porter, T. N.; Martinez, J. A.; Quinn, C. M.; Ablan, S. D.; Freed, E. O.; Nitz, T. J.; Wild, C. T.; Ganser-Pornillos, B. K.; Pornillos, O.; Gronenborn, A. M.; Polenova, T.

doi:10.64898/2026.11.05.764638

bioRxiv · 10.64898/2026.11.05.764638

Structural Basis of Second-Generation HIV-1 Maturation Inhibitor Activity by Magic Angle Spinning NMR

Kumar, K.·Zadorozhnyi, R.·Porter, T. N.·Martinez, J. A.·Quinn, C. M.·Ablan, S. D.·Freed, E. O.·Nitz, T. J.·Wild, C. T.·Ganser-Pornillos, B. K.·Pornillos, O.·Gronenborn, A. M.·Polenova, T.

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Abstract

The CA-SP1 junction of HIV-1 Gag forms a six-helix bundle (6HB) within the immature Gag lattice, sequestering the CA-SP1 cleavage site. Maturation inhibitors (MIs), such as Bevirimat (BVM) and its analogs, are an emerging class of HIV-1 antiviral compounds that stabilize Gag maturation intermediates by interfering with CA-SP1 proteolytic processing. Here, we report the binding modes of a potent second-generation BVM analog with an extended scaffold, HRF-4467, in crystalline CACTD-SP1-NC11 assemblies with inositol hexakisphosphate (IP6), as determined by magic-angle-spinning solid-state NMR (MAS NMR) spectroscopy. The atomic-level structure reveals that HRF-4467 binds asymmetrically in the SP1-NC11 six-helix bundle and stabilizes its helical conformation in the immature lattice, in both the wild-type and the BVM-resistant SP1-V7A Gag variant. Additionally, in the presence of HRF-4467, IP6 adopts distinct conformations in the wild-type CACTD-SP1-NC11 and the SP1-V7A variant. Taken together, our results establish a molecular basis for HRF-4467's improved antiviral activity relative to BVM and suggest strategies for designing inhibitors with enhanced performance against MI-resistant HIV-1 variants for potential therapeutic use.

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Kumar, K., Zadorozhnyi, R., Porter, T. N., Martinez, J. A., Quinn, C. M., Ablan, S. D., Freed, E. O., Nitz, T. J., Wild, C. T., Ganser-Pornillos, B. K., Pornillos, O., Gronenborn, A. M., Polenova, T.. 2026-11-06. Structural Basis of Second-Generation HIV-1 Maturation Inhibitor Activity by Magic Angle Spinning NMR. https://doi.org/10.64898/2026.11.05.764638

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