  Mechanical stretching of six proteins is studied through molecular dynamics
simulations. The model is Go-like, with Lennard-Jones interactions at native
contacts. Low temperature unfolding scenarios are remarkably complex and
sensitive to small structural changes. Thermal fluctuations reduce the peak
forces and the number of metastable states during unfolding. The unfolding
pathways also simplify as temperature rises. In the entropic limit, all
proteins show a monotonic decrease of the extension where bonds rupture with
their separation along the backbone (contact order).
