Biophysical insight into the substrate permeation through the major outer membrane channels of acinetobacter baumannii

Abstract

Among other mechanisms the cause for Multidrug Resistant (MDR) bacteria is their reduced permeability for antibiotics in particular in Gram-negative bacteria such as Acinetobacter baumanii. Owing to the low permeability (100 fold less compared to that of E. coli) and genetic plasticity to adopt to the external environment accompanied with robust efflux pumps aids these bugs in limiting the intracellular active concentration of the antibiotic to minimum. Here we characterize transport of small water soluble molecules across channels in the outer membrane (OM) of A. baumanii. We use Single Channel Electrophysiology as a main tool for the biophysical characterization of the majorly expressed channels from A. baumanii. Combining our study with high resolution X- ray crystallography and molecular dynamics simulations, we provide insight into the OM of A. baumanii.