How much can SNAREs flex their muscles

The high stability of SNARE complexes is probably crucial for their role in membrane fusion, but it has been difficult to measure. A surface-forces apparatus has now been used to measure the stabilization energy of a partially assembled SNARE complex, and the result (35 kBT) is among the highest protein-folding free energies ever observed. Moreover, this approach offers a bright future for further structural and energetic studies of membrane fusion machineries.