Thrombin from complexes with PN1 colored according to B-factors. Ribbon diagram of thrombin is shown in the standard orientation, colored in rainbow according to B-factor (from blue to red, corresponding to B-factors from 20 Å2 to 80 Å2). Thrombin from complex 1 (A) is ordered and mostly blue; however, thrombin from complex 2 (B) is highly disordered (red), particularly in the exosite II region (indicated by oval).