Figure 7
DNAse I footprinting. DNase I footprint on a 236 bp operator fragment (bottom strand shown) using increasing concentrations of YdaT (in tetramer equivalents). The nucleotide sequence of the region that becomes protected is shown at the side with an indication of the regions of protection. The sequence of the 95 nt protected region is indicated on the right. At 0.5 µM YdaT, a 25 bp zone of protection (dark grey background) containing the inverted repeat 5′-TTGATTN6AATCAA-3′ (bold) can already be observed. At higher protein concentrations this zone is extended further on both sides of the primary binding site, resulting in a total footprint of 94–97 nt on both strands that consists of zones of stronger (light grey background) and weaker (white background) protection. The former overlap with two imperfect inverted repeats (bold). These inverted repeats are labelled OL, OM and OR as described in the text. |