The Interaction of Vinculin with Actin
Figure 3
Interaction between vinculin in its closed and open conformation with F-actin along the filament.
(A) The interaction between full-length vinculin in its closed conformation and F-actin is simulated with molecular dynamics. Initially vinculin is with the same orientation relative to F-actin that was used for simulation of Vt. After 15 ns of simulation no stabilizing interactions are formed between vinculin in the closed conformation and F-actin. The closed vinculin makes contact with P333 and R147 of F-actin, as shown in the inset. The contacts result in steric clashes and are followed by movement of vinculin in its closed conformation away from F-actin. (B) A structure of vinculin in its open conformation has previously been suggested [42]. Using this structure, the interaction between vinculin in its open conformation and F-actin is simulated. The vinculin molecule is initially oriented towards actin with the same orientation that was used for simulation of Vt. After 15 ns of simulation the open conformation of vinculin has formed three sets of binding interactions along the actin filament: (1) an interaction if Vt (orange) with S2 of subunit n (top left inset), (2) and interaction of Vt with S1 of subunit n (top right inset), and (3) and interaction of D1 (green) mainly with S3 of subunit n-2 (bottom right inset).