Articles of Significant Interest in This Issue

Abstract

The functional human immunodeficiency virus (HIV-1) envelope glycoprotein (Env) trimer is produced by cleavage of the gp160 precursor. Zhang et al. (e00529-21) find that this Env precursor is conformationally flexible and that this plasticity contributes to the efficiency of cleavage. Cryo-electron microscopy (cryo-EM) structures of the uncleaved Env reveal two asymmetric trimer conformations that potentially allow exposure of epitopes for weakly neutralizing antibodies. Selective pressure to maintain flexibility in the precursor of the functional Env allows the uncleaved Env trimer to sample asymmetric conformations that can misdirect host antibody responses toward ineffective neutralizers.