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. 2024 Feb 2;10(5):eadj0396. doi: 10.1126/sciadv.adj0396

Fig. 1. The HIV-1 Env glycoprotein is structurally dynamic.

Fig. 1.

(A) Linear sequence of the HIV-1 Env with gp120 in blue and gp41 in light orange identifying structural elements layer 1 (navy), layer 2 (purple), variable domains 1 and 2 (V1/V2; green), variable domain 3 (V3; red), β20-β21 (yellow), fusion peptide (FP; cyan), heptad repeat 1 (HR1; orange), heptad repeat 2 (HR2; dark orange), membrane-proximal external region (MPER; brown), transmembrane domain (TM; tan), and the cytoplasmic tail (CT; gray) allosteric elements. CH505 transmitted founder virus glycosylation sites are denoted by gray forks. The black dashed line represents the location at which the SOSIP ectodomains are truncated. (B) Structures of a prefusion closed Env trimer (PDB ID 6UDA, left), an open-occluded Env trimer (PDB ID 5VN8, middle), and an open Env trimer (PDB ID 5VN3, right) from the side viewpoint. Allosteric elements of the gp120 and gp41 domains are colored according to (A). Insets show zoomed-in views of V1/V2, V3, and β20-β21 elements in each conformation.