  Engineering the synthetic nanopores through lipid bilayer membrane to access
the interior of a cell is a long persisting challenge in biotechnology. Here,
we demonstrate the stability and dynamics of a tile-based 6-helix DNA nanotube
(DNT) embedded in POPC lipid bilayer using the analysis of 0.2 microsecond long
equilibrium MD simulation trajectories. We observe that the head groups of the
lipid molecules close to the lumen cooperatively tilt towards the hydrophilic
sugar-phosphate backbone of DNA and form a toroidal structure around the patch
of DNT protruding in the membrane. Further, we explore the effect of ionic
concentrations to the in-solution structure and stability of the lipid-DNT
complex. Transmembrane ionic current measurements for the constant electric
field MD simulation provide the I-V characteristics of the water filled DNT
lumen in lipid membrane. With increasing salt concentrations, the measured
values of transmembrane ionic conductance of the porous DNT lumen vary from 4.3
nS to 20.6 nS. Simulations of the DNTs with ssDNA and dsDNA overhangs at the
mouth of the pore show gating effect with remarkable difference in the
transmembrane ionic conductivities for open and close state nanopores.
