Interaction of the complexin accessory helix with the C-terminus of the SNARE complex: molecular-dynamics model of the fusion clamp.

ABSTRACT: SNARE complexes form between the synaptic vesicle protein synaptobrevin and the plasma membrane proteins syntaxin and SNAP25 to drive membrane fusion. A cytosolic protein, complexin (Cpx), binds to the SNARE bundle, and its accessory helix (AH) functions to clamp synaptic vesicle fusion. We performed molecular-dynamics simulations of the SNARE/Cpx complex and discovered that at equilibrium the Cpx AH forms tight links with both synaptobrevin and SNAP25. To simulate the effect of electrostatic repulsion between vesicle and membrane on the SNARE complex, we calculated the electrostatic force and performed simulations with an external force applied to synaptobrevin. We found that the partially unzipped state of the SNARE bundle can be stabilized by interactions with the Cpx AH, suggesting a s

SUBMITTER: Bykhovskaia M 

PROVIDER: S-EPMC3736676 | biostudies-literature | 2013 Aug

REPOSITORIES: biostudies-literature