Insulin

 Click-hold mouse button to move structure.
Click "x" box to toggle between structures
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  to end view   Aromatic/ Ball&Stick
  Spacefill / wireframe  H bonds (red lines) / wireframe
  Backbone w/Disulfide / Ball&Stick  Salt Bridge (arg-glu) / wireframe
  Polar / wireframe   Non-Polar / wireframe

Color Codes

C

 H

 N

 O

 P

 S

 Cl

 F