Chapter 18, Problem 2AL

Summary Introduction

EMSA stands for electrophoretic mobility shift assay and it is the most common method used to study DNA-protein interactions. This method is also termed as a gel shift assay. This is because the DNA binding protein is added to the purified target DNA mixture and its mobility is slowed down using an agarose gel. The DNA-protein complex is found to be shifted to a higher molecular weight when compared to the DNA without the protein. Usually, the magnitude of the shift is related to the DNA-protein ratio. Thus, the largest shift would be seen when sufficient protein is added.