DNA deformations have been difficult to capture, thus obscuring our understanding of recognition mechanisms. The experiments presented in this thesis uncover, for the first time, rapid (~100-500 microseconds) DNA unwinding/bending attributed to nonspecific interrogation, prior to slower (~5-50 milliseconds) DNA kinking/bending/nucleotide-flipping during recognition. These results help illuminate how a searching protein interrogates DNA deformability and eventually ¿stumbles¿ upon its target site. Submillisecond interrogation may promote preferential stalling of the rapidly scanning protein at cognate sites, thus enabling site-recognition. Such multi-step search-interrogation- recognition processes through dynamic conformational changes may well be common to the recognition mechanisms for diverse DNA-binding proteins.