Fig 5. Gp120 sequence mutation pattern following adaptation to CD4^low targets.

(A) Summary of amino acid mutations acquired as a result of adaptation to long term in vitro culture and adaptation to CD4^low. Green shading indicates mutations affecting N-linked glycosylation sites. Red boxes denote mutations that occur in both CD4^low adapted clones, yellow and orange boxes indicate mutations that occurred only in CD4^low.c21 and CD4^low.c24, respectively. (B) Structural representations of mutated residues in NAB01 associated with adaptation to low levels of CD4 mapped onto crystal structure 5fyj of X1193.c2 SOSIP [100]. Dark gray residue shading indicates limits of non-resolved region of gp120 V4 loop. Missing from the model are the residue at 402, within the non-resolved region of V4, and the glycans at residues 408 and 461 which are not present on this subtype G Env variant. Structure rendered using PyMol version 1.4.1 [101].