Design and application of stimulus-responsive peptide systems.

The ability of peptides and proteins to change conformations in response to external stimuli such as temperature, pH and the presence of specific small molecules is ubiquitous in nature. Exploiting this phenomenon, numerous natural and designed peptides have been used to engineer stimulus-responsive systems with potential applications in important research areas such as biomaterials, nanodevices, biosensors, bioseparations, tissue engineering and drug delivery. This review describes prominent examples of both natural and designed synthetic stimulus-responsive peptide systems. While the future looks bright for stimulus-responsive systems based on natural and rationally engineered peptides, it is expected that the range of stimulants used to manipulate such systems will be significantly broadened through the use of combinatorial protein engineering approaches such as directed evolution. These new proteins and peptides will continue to be employed in exciting and high-impact research areas including bionanotechnology and synthetic biology.