A method of altering the conformation of a polypeptide having a known three-dimensional structure is described. The method comprises attaching a first end of a polymer to a first portion of the polypeptide, attaching a second end of the polymer to a second portion of the polypeptide, and altering the mechanical tension of the polymer, thereby altering the conformation of the polypeptide. The alteration of the conformation of the polypeptide may increase or decrease the binding affinity of the polypeptide for a substrate bound by the polypeptide, or alter the catalytic rate of an enzyme. Typically, the polymer is a polynucleotide or polypeptide.