Electromechanical transduction: reduction-driven hydrophobic folding demonstrated in a model protein to perform mechanical work.

It has long been appreciated that hydrophobic folding is an important element of protein structure formation. Here it is demonstrated for the first time that the electrochemical or chemical reduction of a nicotinamide in a model protein, which increases hydrophobicity, can drive hydrophobic folding and assembly in such a way as to lift a weight or otherwise contract against a constant tensional force. The model protein, poly[0.73(GVGVP),0.27(GK(NMeN)GVP], can be gamma-irradiation cross-linked to form an elastic matrix which contracts on raising the temperature from below to above the transition range for hydrophobic folding and assembly. On reduction of the N-methyl nicotinamide, (NMeN), the transition temperature range is lowered from above to below 20 degrees C to drive contraction due to hydrophobic folding with the performance of mechanical work.