Multidisciplinary studies with mutated HIV-1 capsid proteins reveal structural mechanisms of lattice stabilization

• Published in: Nature communications Vol. 14; no. 1; pp. 5614 - 12
• Main Authors: Gres, Anna T, Kirby, Karen A, McFadden, William M, Du, Haijuan, Liu, Dandan, Xu, Chaoyi, Bryer, Alexander J, Perilla, Juan R, Shi, Jiong, Aiken, Christopher, Fu, Xiaofeng, Zhang, Peijun, Francis, Ashwanth C, Melikyan, Gregory B, Sarafianos, Stefan G
• Format: Journal Article
• Language: English
• Published: England Nature Publishing Group 12.09.2023; Nature Publishing Group UK; Nature Portfolio
• Subjects: Biophysics; Capsid; Capsid Proteins - genetics; Cryoelectron Microscopy; Crystal lattices; Electron microscopy; Electrostatic properties; Electrostatics; Helices; Hexamers; HIV; HIV-1 - genetics; Human immunodeficiency virus; Infectivity; Molecular dynamics; Multidisciplinary research; Mutation; Uncoating
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-023-41197-7

HIV-1 capsid (CA) stability is important for viral replication. E45A and P38A mutations enhance and reduce core stability, thus impairing infectivity. Second-site mutations R132T and T216I rescue infectivity. Capsid lattice stability was studied by solving seven crystal structures (in native background), including P38A, P38A/T216I, E45A, E45A/R132T CA, using molecular dynamics simulations of lattices, cryo-electron microscopy of assemblies, time-resolved imaging of uncoating, biophysical and biochemical characterization of assembly and stability. We report pronounced and subtle, short- and long-range rearrangements: (1) A38 destabilized hexamers by loosening interactions between flanking CA protomers in P38A but not P38A/T216I structures. (2) Two E45A structures showed unexpected stabilizing CA -CA inter-hexamer interactions, variable R18-ring pore sizes, and flipped N-terminal β-hairpin. (3) Altered conformations of E45A α9-helices compared to WT, E45A/R132T, WT , WT , and WT decreased PF74, CPSF6, and Nup153 binding, and was reversed in E45A/R132T. (4) An environmentally sensitive electrostatic repulsion between E45 and D51 affected lattice stability, flexibility, ion and water permeabilities, electrostatics, and recognition of host factors.