Integration of a Synthetic Molecular Motor Into a Rotary DNA Nanostructure: A Framework for Single-Molecule Actuation

Synthetic molecular motors are an appealing means to control motion at the nanoscale, but understanding their behaviour as single-molecule actuators and integrating them into larger, functional systems remain technical challenges. Translating molecular actuation into coordinated device-level behaviour requires precise placement and orientation of the motors: DNA origami provides a powerful platform for positioning molecules with nanometre precision. Here, we demonstrate integration of a light-driven, rotary molecular motor into a DNA-based nanoscale actuator through site-specific, four-point conjugation. The motor is labelled with four distinct oligonucleotides, two on each side, using DNA-templated chemistry. This modular approach enables stable, oriented incorporation of the motor into a DNA assembly through DNA hybridization. Upon photoactivation with UV light, the motor transduces photon energy into rotary motion. By coupling the motor to a fluorescently labelled DNA rotor arm we amplify its movement and enable real-time observation using total internal reflection fluorescence microscopy. A subset of assembled devices exhibits light-induced conformational transitions and directional motion consistent with the expected photochemical mechanism. These results establish a programmable framework for integration of light-driven molecular motors into synthetic nanomachines and tools for the study of their behaviour.