Biomedicine Nanopore Sequencing to Identify DNA Bases A British company has demonstrated an important step for a new sequencing technique. by Katherine Bourzac February 24, 2009 Sponsored by A DNA base (red) passes through a protein tunnel lined with a sugar (blue and green bubbles). The sugar slows down the DNA as it moves through the pore, allowing time for the base to be identified. This artist’s illustration shows the technique that Oxford Nanopore hopes to use to sequence complete strands of DNA. In the first step, a strand moves through an enzyme attached to a protein pore embedded in a lipid membrane. Next, the enzyme cleaves the DNA bases off one by one. As each base is released, it passes through a protein pore, where it is identified by its effect on the flow of electrical current through the pore. The company has demonstrated all the components of this system and shown that it can identify DNA bases. It has not yet integrated the nanopore with the enzyme, however.