Approximately 11% smaller t-/v-SNARE ring complexes are generated using 50 nm cholesterol-associated vesicles as opposed to vesicles containing L-alpha-lysophosphatidylcholine (LPC), as observed using atomic force microscopy. Circular dichroism spectroscopy demonstrated that in the presence of LPC as opposed to cholesterol, N-ethylmaleimide-sensitive factor + adenosine triphosphate induces disassembly of beta-sheet structures but not the a-helical contents within the t-/v-SNARE complex.