From FoldIt Wiki

[edit] Visualization/Camera

   Rotate:  Click and Drag on background
   Move:    Right Click / Command Click and drag on background
   Zoom:    Scroll / Shift and move

[edit] Mouse Controls - 3 button mapping

   Left   - Drag (Nudge)
   Center - Shift for middle-click / drag
   Right  - Ctrl/Cmd for right click / drag

[edit] Pull mode

The following features only function in Pull Mode.

   Left drag - Pull on selected structure
   Middle Click - Lock single residue
   Middle Drag - Apply rubber band between selected structures
   Right Click - Context menu-lock structure
               - Wiggle Structure
               - Rebuild structure