Figure 1.

Local reversions in HIV-1 gp120. A. Schematic of gp120 with the 5 conserved domains (C1–C5 and five variable domains (V1–V5). The location of the V4 base disulfide bond is indicated (grey sphere). The figure is adapted from [17] and sites for N-linked glycosylation are shown. B. Local reversions after evolution. A detailed description of the evolution is given in materials and methods section. Sequences of the V4 loop and flanking regions of wt, mutant and revertant viruses. The original C418A mutation is indicated with a grey box, the reversions with black boxes. The sequences of revertant 1 are from day 39 after transfection (both 1a and 1b were derived from the day 39 sample). The sequences of revertant 2 are from day 77 (2a) and day 136 (2b) after transfection. Revertant 2 also contained reversions outside the indicated domain: T188N, N230D and R696K at day 77, and A316T, N339Y in addition to these at day 136. C. Locations of the reverted residues on the 3D structure of gp120. Ribbon diagram of the crystallized core of gp120 [53] with residue 418 in yellow and the reversions in red. Note that several reversions in R2 are not indicated because they are located outside the crystallized core (residues 188 and 316 (located in the V2 and V3, respectively), and residue 696 in gp41).