Table 1. Amino acids frequency at the second position of the GxGR tetramer of V3 loop of HIV-1 subtype B.
| Amino Acid | Pandemic Isolates (n = 8131)* | Brazilian Isolates (n = 333) |
| P | 7689 (94.55%) | 161 (48.4%) |
| L | 202 (2.5%) | 19 (5.7%) |
| W | 60 (0.74%) | 102 (30.6%) |
| Q | 66 (0.81%) | 2 (0.6%) |
| F | 12 (0.15%) | 35 (10.5%) |
| M | 22 (0.27%) | 3 (0.9%) |
| R | 22 (0.27%) | 3 (0.9%) |
| others | 58 (0.71%) | 8 (2.4%) |
*) Sequences from worldwide countries. All sequences were obtained from the Los Alamos HIV-1 database (http://www.hiv.lanl.gov/).
P = proline; L = leucine; W = tryptophan; Q = glutamine;
F = phenylalanine; M = Methionine; R = Arginine.
Others = alanine, lysine, serine, glycine, valine, histidine, threonine and tyrosine.