Mobility Shift Assays

The electrophoretic mobility shift assay (EMSA, also known as the gelshlft, gel retardation, or bandshift assay) is a technique that is widely used to study interactions between proteins and nucleic acids The assay is simple to perform, because it requires little specialized equipment and only small quantities of the protein to be studied, yet it can yield detailed informatlon about the binding speclficlty of a protein, the kinetics of the binding reaction, and the structural consequences of the protein- DNA interaction Unlike other techniques, such as nitrocellulose filter binding assays, EMSA can also be used to gain informatlon about the stoichiometry of protein- DNA complexes and to study interactlons between proteins within a multlprotein- DNA complex