Dynamic Conformational Changes in MUNC18 Prevent Syntaxin Binding
Figure 1
Dynamic equilibrium between several open- and closed-cavity conformations of wild-type munc18a.
A) Structure of munc18a (3C98.pdb). B) Ribbon presentation of syntaxin-1a-munc18a complex including the location of the munc18a phosphorylation sites (Ser 306 and Ser 313) and adjacent residues of syntaxin-1a (Asp 140 and Glu 143). C) Time-dependent change in the distance between the centers of mass of domains 1 and 3a during the wild-type munc18a simulation (simulation 1). D) The distance between residues Gly 26 and Glu 273. E) Histogram of the distribution of the distance between Gly 26 and Glu 273. F–G) Porcupine plots based on ED analysis of two of the main motion vectors (the first and the fourth) of munc18a wild-type; the direction and the length of the ‘needles’ in blue indicate the direction and extent of the motion respectively. Closure motion of the cavity (F) opening motion of the cavity (G).