Energy-Dependent Disassembly of Self-Assembled SNARE Complex: Observation at Nanometer Resolution Using Atomic Force Microscopy

Full-length v-SNARE protein reconstituted in lipid vesicles, when exposed to t-SNARE-reconstituted lipid membrane, results in the self-assembly of a t-/v-SNARE complex in a ring pattern, forming pores and the establishment of continuity between the opposing bilayers. In contrast, when v-SNARE protein alone (without liposomes) is exposed to t-SNARE-reconstituted lipid membrane, they also self-assemble to form t-/v-SNARE complexes, although such complexes fail to possess the characteristic ring pattern, nor do they help in the establishment of continuity between the opposing bilayers. Hence, t-SNAREs and v-SNARE need to be membrane-associated to interact in a circular array to form conducting pores in the presence of calcium. This study demonstrates that, irrespective of their arrangement, both forms of the SNARE complex can be disassembled in the presence of NSF-ATP.