Scientists from China and Canada have studied the effect of a DNA-binding antigen-binding fragment (Fab) of an antibody on the translocation of a DNA polymer. Both poly(dT)45:Fab HED10 and poly(dT)45 produce unique double step current traces, which were analysed in detail to get information about the translocation events.
The results have important implications for understanding the translocation behaviour of polymers, which could help to develop nanopore biosensors with high sensitivity and specificity, says Yitao Long, from East China University of Science and Technology. In particular, the addition of polymer-binding antibodies may facilitate the use of nanopores in sequencing technologies.
The presence of the FAB HED10 decreases the time of the first level of the step but not the second. The Fab appears to behave as a rudder, which significantly decreases the energy barrier for poly(dT)45 translocation. A more rigid or extended conformation of poly(dT)45 would decrease the time required to find the entrance to the narrow constriction in the pore. The entropic barrier required to linearise the DNA strand may be the dominant contribution to the entire energy barrier.
Find out more by downloading the communication, recently published in ChemComm.
