FIG 7.

Mutations at residues 87 and 99 alter properties of the immature lattice. The effects of mutations on the Gag lattice structure were predicted based upon the WT MD model of Goh et al. (46). (A) D87A alters the conformations adopted by R89 and its network of interactions. Hydrogen bonds are shown as black lines. (B) The flexibility of residues 90 to 95 in the FL large loop is markedly increased upon D87A mutation as reflected by RMSF. (C) Surface electrostatic potential maps show that the removal of negative charges by D87A or E99Q leads to accumulation of positive charge at the interhexameric interface (black arrows). Only the NTD is shown for clarity. (D) The D87E change alters the interactions of residue E41 at the NTD dimer interface. E41 interacts with R141 and R145 (black lines) across the interface in WT but favors contact with Q138 and R145 in the D87E lattice. Helices 2 and 7 are shown as solid ribbons and the remainder of the NTD as translucent ribbons.