Gag, the primary structural protein of HIV-1, is recruited to the plasma membrane for virus assembly by its matrix (MA) domain. Gag is subsequently cleaved into its component domains, causing structural maturation to repurpose the virion for cell entry. We determined the structure and arrangement of MA within immature and mature HIV-1 through cryo–electron tomography. We found that MA rearranges between two different hexameric lattices upon maturation. In mature HIV-1, a lipid extends out of the membrane to bind with a pocket in MA. Our data suggest that proteolytic maturation of HIV-1 not only assembles the viral capsid surrounding the genome but also repurposes the membrane-bound MA lattice for an entry or postentry function and results in the partial removal of up to 2500 lipids from the viral membrane.

Gag 是 HIV-1 的主要结构蛋白，通过其基质 (MA) 结构域被募集到质膜以进行病毒组装。Gag 随后被切割成其组成结构域，导致结构成熟以重新利用病毒粒子进入细胞。我们通过低温电子断层扫描确定了未成熟和成熟 HIV-1 中 MA 的结构和排列。我们发现 MA 在成熟时会在两个不同的六聚体晶格之间重新排列。在成熟的 HIV-1 中，一种脂质从膜中伸出，与 MA 中的一个口袋结合。我们的数据表明，HIV-1 的蛋白水解成熟不仅组装了围绕基因组的病毒衣壳，而且还将膜结合的 MA 晶格重新用于进入或进入后功能，并导致从病毒膜上部分去除多达 2500 种脂质。