Electrostatic Switch Function in the Mechanism of Protein Kinase A I Activation: Results of the Molecular Dynamics Simulation

Figure 3

A-domain conformational transition, event F. (a) Before event F. (b) After event F. Side chains of I204, L135, F136, and L139 are shown with grey spheres of van der Waals radii. In (a), L233 and M234 do not form favorable hydrophobic contacts with other residues. In (b), L233 and M234 rotate to N3A-motif and PBC, respectively, and acquire a favorable hydrophobic environment. This rotation is accompanied by transition of B/C-helix turn (a.a. 229–234, marked with dark blue) to π-form, which exhibits a lower curvature degree as compared with α-form.

(a)

(b)