The Cruciform DNA Mobility Shift Assay: A Tool to Study Proteins that Recognize Bent DNA

So-called architectural DNA binding proteins such as those of the HMGB-box family induce DNA bending and kinking. However, these proteins often display only a weak sequence preference, making the analysis of their DNA binding characteristics difficult if not impossible in a standard electrophoretic mobility assay (EMSA). In contrast, such proteins often bind prebent DNAs with high affinity and specificity. A synthetic cruciform DNA structure will often provide an ideal binding site for such proteins, allowing their affinities for both bent and linear DNAs to be directly and simply determined by a modified form of EMSA.