Ji Hyun Lee:
May I suggest this very useful review of electrophoretic techniques for
studying protein DNA interactions, as it appears to address the questions
you and others have raised:
"Use of gel retardation to analyze protein-nucleic acid interactions"
D. Lane, P. Prentki, and M. Chandler.
Microbiological Reviews 56: 509-528, 1992
Good luck.
Fritz Coffman
UMDNJ Dept. of Pathology