Description: A landmark in HIV structural biology, this structure reveals the first crystal structure of a soluble, cleaved HIV-1 Env trimer (BG505 SOSIP.664) in complex with the broadly neutralizing antibody PGT122. It shows the prefusion state of gp41, the gp120/gp41 interface, and the stabilizing V1/V2/V3 apex architecture, providing a foundational blueprint for structure-based HIV vaccine design.