Figure 4
From: Modulation of the Neisseria gonorrhoeae drug efflux conduit MtrE
(a) Red dots display the experimental current-voltage relationship in symmetrical 210 mM KCl solution, black dots show the current/voltage relationship obtained from the MD simulations near the experimental voltage range. Voltages of ±0.05, ±0.10 and ±0.25 V were applied along the z-axis using external electric fields as implemented in GROMACS57, together with the charmm36 force field and positional restraints of 200 kJ/mol · nm2 on MtrE heavy atoms as detailed in the text. We observe excellent agreement between the experimental and the computational currents. The computational x-axis and the experimental x and y-axis error bars are smaller than the data points. (b, bottom) Sequence alignment of the three electrophysiologically characterised efflux OMPs. MtrE shows an abundance of arginine residues in the periplasmic loop region in addition to a series of aspartate residues lining the interior of the pore, which is not present in homologous proteins. (b, top) The density map of K+ (contoured at 2% SD, in red) and Cl− (contoured at 5% SD, in blue) highlights the influence of this highly basic region on ion flow through the channel.
