ComEA Is Essential for the Transfer of External DNA into the Periplasm in Naturally Transformable Vibrio cholerae Cells
Figure 5
ComEA but not ComEAK62/63A binds to DNA in vitro.
EMSA using the 200comEA gene as a probe (panels A and B). A total of 0.4 pmol of DNA was incubated without or with increasing amounts of the ComEA-mCherry-Strep (A) and ComEAK62/63A-mCherry-Strep (B) protein (lanes 2 to 10: 0, 2, 4, 6, 8, 10, 12, 16, and 20 pmol of protein). Free DNA, free protein, and the DNA/protein complex are indicated by the arrows. L: DNA ladder (representative bp are indicated on the left). Panel C: AFM images of DNA, proteins, and DNA/protein complexes absorbed on mica. AFM images from left to right: bare DNA fragments (DNA to protein ratio 1∶0); DNA/protein complex at a molecular ratio of 1∶2.5; DNA/protein complex at a molecular ratio of 1∶10. The proteins bound to the DNA are marked with black arrows; unbound proteins are labeled by white arrows. The height or Z scale is shown on the right and is the same for all three panels displaying 270 nm×270 nm scan areas.