Chemically Fueled Communication Along a Scaffolded Nanoscale Array of Squaramides

Area of Science:

• Supramolecular Chemistry
• Molecular Engineering
• Biomimetic Systems

Background:

• Allosterically regulated proteins function by relaying conformational changes over nanometer distances.
• Artificial systems capable of mimicking this protein mechanism are needed for molecular communication tools.
• This requires nanometer-scale molecules that reversibly switch between defined shapes upon signaling molecule detection.

Purpose of the Study:

• To design and synthesize artificial molecular switches capable of relaying conformational changes over nanometer distances.
• To investigate the use of hydrogen-bond relays on rigid scaffolds for reversible shape switching.
• To demonstrate communication of molecular signals to a distant site using these artificial systems.

Main Methods:

• Utilized 1.8 nm rigid rod oligo(phenylene-ethynylene) scaffolds.
• Incorporated switchable multi-squaramide hydrogen-bond relays with director groups.
• Investigated orientation changes in response to proton signals (acid-base cycles) and chemical fuel.
• Monitored relay orientation via a terminal NH group 1.8 nm away.

Main Results:

• Achieved reversible switching of hydrogen-bond relay orientation (parallel/antiparallel) on the scaffold.
• Demonstrated that an amine director group responds to proton signals, inducing multiple orientation changes.
• Showcased how a chemical fuel can act as a dissipative signal, causing the relay to revert to its original orientation.
• Successfully relayed information about molecular signals over a 1.8 nm distance.

Conclusions:

• Developed nanometer-sized molecular switches that mimic protein allostery.
• Established a system for reversible, signal-responsive conformational changes at the molecular level.
• Demonstrated the potential for communicating information from out-of-equilibrium molecular signals to distant sites.