Fig. 6
From: The β20–β21 of gp120 is a regulatory switch for HIV-1 Env conformational transitions
Interaction between residues in the gp120 β20–β21 element and the V1/V2 region. a The individual and combined effect of changes in Ile 423 and Leu 193 on the sensitivity of HIV-1 to ligands recognizing downstream conformations. Results shown are averages of those obtained in two or three independent experiments and error bars represent s.e.m. Indicated P values were calculated using a two-sample t test. b Leu 193 and Ile 423 were mapped on a structure of HIV-1 Env bound to the PGT151 antibody (PDB ID 5FUU)36. c Analysis of the prevalence of amino acids other than isoleucine at position 423 or leucine at position 193 among 2500 primary HIV-1 strains. Green pie plots show the prevalence in all HIV-1 strains and residue-specific pie plots (set to the same size as the green plots) show the prevalence of specific amino acids within the HIV-1 subpopulation that carries amino acids other than isoleucine at position 423 or leucine at position 193. d Possible combinations of different amino acids at Env residues 193 and 423 in primary HIV-1 strains. The number of isolates with the specified pairing is indicated
