Figure 2.

Trimeric model of the fusion domains S-MHV-A59 (PP), S-MHV-2 (P), energy landscapes, and their internal FPs. a, the sequence comparison of FP between S-MHV-A59 (PP) and S-MHV-2 (P) shows that S-MHV-A59 (PP) has two consecutive central prolines. A trimeric model of the fusion domain of S-MHV-A59 (PP) spanning residues 871–1116 from PDB structure 3JCL is shown in b, and the comparative model for the trimeric fusion domain was built from 3JCL for S-MHV-2 (P) spanning residue locations 911–1153 in c. The FP segment highlighted in b is also marked in a blue cartoon diagram, and proline is shown in a ball-and-stick model (d). The corresponding FP from S-MHV-2 (P) is shown in e. The snapshots shown are representatives of the largest structural clusters obtained from the MD simulation trajectories. Energy landscapes from simulation of trimeric S-MHV-A59 (P) and S-MHV-A59 (PP) show double potential wells. The population of the conformers in the trajectory can be assessed by the relative energy scale given in the key. It is also observed that the mutant S-MHV-A59 (P) has comparatively shallow potential wells (f).