Figure 2

Epistatic codons and CD4 levels. Upper panel of each page shows the correlation between epistatic pairs and CD4+ T cell counts. The x-axis depicts the distinct combinations of amino acids (pairs), y-axis shows the levels of CD4+ T cell counts measured as number of cell per mm3 of plasma. Lower panel shows the location of epistatic sites (orange dots) on the structure of a computational model (Balaji et al., Bioinformation. 2006 Dec 6;1:290-309[PMID: 17597910], PDB=1VZF) of Vif Protein of HIV-1. Yellow regions depict the SOCS BOX (BC Box+Cullin Box) and grey regions are A3 binding sites (see text for more details). Visualization and edition of structures were done using PyMOL software (http://www.pymol.org).