Distinct Target Site of Lenacapavir in Immature HIV-1 and Concurrent Binding with the Maturation Inhibitor Bevirimat

HIV-1 inhibitors, such as bevirimat (BVM) and lenacapavir (LEN), significantly reduce the production and maturation of infectious virions. However, their mechanisms remain unclear due to the absence of high-resolution structures for BVM in complex with the immature Gag lattice and LEN's structural data being limited to the mature capsid. Utilizing perforated virus-like particles (VLPs) produced from mammalian cells, we determined in situ cryo-electron microscopy (cryo-EM) structures of HIV-1 with inhibitors. This allowed for the first structural determination of the native immature HIV-1 particle with BVM and LEN bound inside the VLPs at high resolutions. Our findings demonstrate that LEN not only binds the mature capsid but also targets the immature lattice in a distinct manner. The binding of LEN induces a conformational change in the capsid protein (CA) region and alters the architecture of the Gag lattice, which may affect the maturation process. In addition, a more accurate model of BVM engaging the Gag lattice is revealed, one that is independent of LEN binding. These insights expand our understanding of the inhibitory mechanisms of LEN and BVM on HIV-1 and provide valuable clues for the design of future inhibitors.