An ion signal responsive dynamic protein nano-spring constructed by high ordered host-guest recognition.

A protein self-assembly nano-spring was developed through host-guest interactions between cucurbit[8]uril and tripeptide FGG tags of fusion protein FGG-recoverin-GST. Fine control of the conformational changes of the Ca2+-responsive domain allows for a 50% stretch of the protein nano-spring as it switches from the contracted state to the extended state.