Fig. 4.

Detergent micelles reduce the stability and folding rate of gp41. (A) FECs of gp41-ll and gp41-sl in 4 mM DPC and gp41-ll-ext in 0.5% Triton. The FECs were obtained by pulling (black) and then relaxing (gray) a single gp41 complex and fit by the worm-like chain model (red). (B) Extension-time trajectories of gp41-ll, gp41-sl, or gp41-ll-ext under the indicated forces showing transitions between the six-helix and the five-helix states in DPC or Triton. The idealized transitions derived from HMM are shown in red. (C) Force-dependent unfolding probabilities (Upper) and transition rates (Lower) of gp41-ll (black) and gp41-sl (purple) in DPC or gp41-ll-ext (red) in Triton. The measurements (symbols) were fit by the theoretical model (lines).