Plasmid AFM (IMAGE) Duke University Caption An atomic force microscopy image shows a four-part complex of the protein RepA (bright mounds) bound together and "handcuffing" two thread-like strands of DNA plasmid. Credit University of Nebraska Medical Center Nanoimaging Core Facility Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.