title: General Method to Determine the Flux of Charged Molecules through Nanopores Applied to β-Lactamase Inhibitors and OmpF.
abstract: A major challenge in the discovery of the new antibiotics against Gram-negative bacteria is to achieve sufficiently fast permeation in order to avoid high doses causing toxic side effects. So far, suitable assays for quantifying the uptake of charged antibiotics into bacteria are lacking. We apply an electrophysiological zero-current assay using concentration gradients of β-lactamase inhibitors combined with single-channel conductance to quantify their flux rates through OmpF. Molecular dynamic simulations provide in addition details on the interactions between the nanopore wall and the charged solutes. In particular, the interaction barrier for three β-lactamase inhibitors is surprisingly as low as 3-5 kcal/mol and only slightly above the diffusion barrier of ions such as chloride. Within our macroscopic constant field model, we determine that at a zero-membrane potential a concentration gradient of 10 μM of avibactam, sulbactam, or tazobactam can create flux rates of roughly 620 molecules/s per OmpF trimer.
authors.affiliation: Department of Life Sciences and Chemistry, Jacobs University Bremen , 28719 Bremen, Germany.
authors.forename: Ishan
authors.initials: I
authors.lastname: Ghai
authors.affiliation: Department of Physics, University of Cagliari , Cagliari 09124, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Pira
authors.affiliation: Department of Biomedical Sciences, University of Cagliari , Cagliari 09124, Italy.
authors.forename: Mariano Andrea
authors.identifier: http://orcid.org/0000-0001-7502-7265
authors.initials: MA
authors.lastname: Scorciapino
authors.affiliation: Department of Physics, University of Cagliari , Cagliari 09124, Italy.
authors.forename: Igor
authors.initials: I
authors.lastname: Bodrenko
authors.affiliation: Department of Life Sciences and Chemistry, Jacobs University Bremen , 28719 Bremen, Germany.
authors.forename: Lorraine
authors.initials: L
authors.lastname: Benier
authors.affiliation: Department of Physics, University of Cagliari , Cagliari 09124, Italy.
authors.forename: Matteo
authors.identifier: http://orcid.org/0000-0003-4272-902X
authors.initials: M
authors.lastname: Ceccarelli
authors.affiliation: Department of Life Sciences and Chemistry, Jacobs University Bremen , 28719 Bremen, Germany.
authors.forename: Mathias
authors.initials: M
authors.lastname: Winterhalter
authors.affiliation: Department of Life Sciences and Chemistry, Jacobs University Bremen , 28719 Bremen, Germany.
authors.forename: Richard
authors.identifier: http://orcid.org/0000-0001-5472-8097
authors.initials: R
authors.lastname: Wagner
mesh_terms: D000900:Anti-Bacterial Agents / Q000493:pharmacokinetics*; D053961:Azabicyclo Compounds / Q000493:pharmacokinetics; D008564:Membrane Potentials; D056004:Molecular Dynamics Simulation; D058608:Nanopores; D010397:Penicillanic Acid / Q000031:analogs & derivatives / Q000493:pharmacokinetics; D013407:Sulbactam / Q000493:pharmacokinetics; D000078142:Tazobactam; D065093:beta-Lactamase Inhibitors / Q000493:pharmacokinetics*
chemical_list: D000900:Anti-Bacterial Agents; D053961:Azabicyclo Compounds; D065093:beta-Lactamase Inhibitors; C543519:avibactam; D010397:Penicillanic Acid; D013407:Sulbactam; D000078142:Tazobactam