Research Article

Evidence of Divergent Amino Acid Usage in Comparative Analyses of R5- and X4-Associated HIV-1 Vpr Sequences

Figure 1

Reduced alphabets utilized for analysis of Vpr amino acid variation. The 20 standard amino acids were grouped according to BLOSUM50 correlations in a hierarchical manner as previously reported in [21]. The resulting alphabets were designated as Murphy-15, Murphy-10, Murphy-8, and Murphy-4. Colors represent amino acids grouped in each alphabet according to physiochemical properties (M15, M10, M8, and M4, resp.).