A protease-resistant core domain of the neuronal SNARE complex consists of an α-helical bundle similar to the proposed fusogenic core of vital fusion proteins [Skehel, J. J. and Wiley, D. C. (1998) Cell 95, 871-874]. We find that the isolated core of a SNARE complex efficiently fuses artificial bilayers and does so faster than full length SNAREs. Unexpectedly, a dramatic increase in speed results from removal of the N-terminal domain of the t- SNARE syntaxin, which does not affect the rate of assembly of v-t SNARES. In the absence of this negative regulatory domain, the half-time for fusion of an entire population of lipid vesicles by isolated SNARE cores (≃10 min) is compatible with the kinetics of fusion in many cell types.
|Number of pages
|Proceedings of the National Academy of Sciences of the United States of America
|Published - 26 Oct 1999