Fig 1.

(A) gp120_YU2 homology model with labeled variable loop regions and colored by domain: inner (charcoal), outer (maroon) and bridging sheet (orange). (B) gp120_YU2 homology model fitted to electron microscopy density data (EMDB 5018 [76], 5553 [77]) from a side view (left) and top-down (right) perspective, demonstrating the trimeric arrangement of gp120 protomers and illustrating the orientation of the V1/V2 (charcoal) and V3 (orange) loop regions relative to each other and the viral membrane.