18 research outputs found
Electromechanical Signatures for DNA Sequencing through a Mechanosensitive Nanopore
Biological
nanopores have been extensively used for DNA base detection
since these pores are widely available and tunable through mutations.
Distinguishing bases of nucleic acids by passing them through nanopores
has so far primarily relied on electrical signals–specifically,
ionic currents through the nanopores. However, the low signal-to-noise
ratio makes detection of ionic currents difficult. In this study,
we show that the initially closed mechanosensitive channel of large
conductance (MscL) protein pore opens for single-stranded DNA (ssDNA)
translocation under an applied electric field. As each nucleotide
translocates through the pore, a unique mechanical signal is observedî—¸specifically,
the tension in the membrane containing the MscL pore is different
for each nucleotide. In addition to the membrane tension, we found
that the ionic current is also different for the four nucleotide types.
The initially closed MscL adapts its opening for nucleotide translocation
due to the flexibility of the pore. This unique operation of MscL
provides single nucleotide resolution in both electrical and mechanical
signals. Finally, we also show that the speed of DNA translocation
is roughly 1 order of magnitude slower in MscL compared to Mycobacterium smegmatis porin A (MspA), suggesting
MscL to be an attractive protein pore for DNA sequencing