HOMODIMER OF P50(NF-KAPPA-B1) DOES NOT INTRODUCE A SUBSTANTIAL DIRECTED BEND INTO DNA ACCORDING TO 3 DIFFERENT EXPERIMENTAL ASSAYS

Transcription factors can distort the conformation of the DNA double helix upon binding to their target sites. Previously, studies utilizing circular permutation-electrophoretic mobility shift assay suggested that the homodimer of p50 (NF kappa B1), canonical NF-kappa B (p65-p50), as well as several non-canonical NF-kappa B/Rel complexes, may induce substantial DNA bending at the binding site. Here we have applied three additional experimental approaches, helical phasing analysis, minicircle binding and cyclization kinetics, and conclude that the homodimer of p50 introduces virtually no directed bend into the consensus kappa B sequences GGGACTTTCC or GGGAATTCCC.