FIG. 3.

Effect of single amino acid substitutions in HR1 on sensitivity to HR2 peptides. MLV(EnvA) pseudotypes were generated with either wild-type ASLV-A envelope (diamonds) or HR1 mutants T55A (triangles), L62A (squares), or R69E (circles). Virus was incubated with either R102 (A) or R99 (B) for 2 min at room temperature prior to challenging QT6 cells. Percent infectivity is relative to the titer in the absence of peptide. Data points are the averages of three experiments (wild type and L62A) with error bars marking standard deviations, or they are from a single representative experiment (T55A and R69E).