Effects of nanopore charge decorations on the translocation dynamics of DNA

We have investigated the dynamics of single-stranded DNA as it translocates through charge mutated protein nanopores. Translocation of DNA is a crucial step in nanopore-based sequencing platforms, where control over translocation speed remains as one of the main challenges. Taking advantage of the interactions between negatively charged DNA and positively charged amino acid residues, the translocation speed of DNA can be manipulated by deliberate charge decorations inside the nanopore. We employed coarse grained Langevin dynamics simulations to monitor the step-by-step movement of the DNA through different mutations of α-hemolysin protein nanopores. We found that although the average translocation time per nucleotide is longer in agreement with experiments, the DNA nucleotides do not translocate with a uniform speed. Furthermore, the location and the spacing of the charge decorations can alter the translocation dynamics significantly, trapping DNA in some cases. Our findings can give insights when designing charge patterns in nanopores.