# Substrate specificity of Burkholderia pseudomallei multidrug transporters is influenced by the hydrophilic patch in the substrate‐binding pocket

## TL;DR

This study shows that a hydrophilic patch in the substrate-binding pocket of BpeB and BpeF transporters in Burkholderia pseudomallei affects their drug resistance and substrate specificity.

## Contribution

The study identifies the role of a hydrophilic patch in determining the substrate specificity of BpeB and BpeF multidrug transporters in B. pseudomallei.

## Key findings

- Mutant analyses showed up to a 64-fold increase in drug susceptibility compared to wild-type transporters.
- BpeB mutants exhibited increased resistance to aminoglycosides, which are not transported by the wild-type protein.
- The hydrophilic patch in the substrate-binding pocket is involved in substrate specificity of BpeB and BpeF.

## Abstract

The Gram‐negative pathogen Burkholderia pseudomallei possesses multiple resistance‐nodulation‐division superfamily transporters that contribute to multidrug resistance, including BpeB and BpeF. Structural studies of BpeB and BpeF have identified a hydrophilic patch in their substrate‐binding pocket. To investigate the relationship between this hydrophilic patch and substrate specificity, mutant analyses were performed using an Escherichia coli recombinant expression system. Drug susceptibility tests of BpeB and BpeF mutants showed up to a 64‐fold increase in susceptibility compared with the wild type. Growth curve analyses revealed that BpeB mutants exhibited increased resistance to aminoglycosides, which are not transported by the wild type. These findings suggest that the hydrophilic patches in the substrate‐binding pockets of BpeB and BpeF are involved in the substrate specificity.

Multidrug transporters BpeB and BpeF from the Gram‐negative pathogen Burkholderia pseudomallei have a hydrophilic patch in their substrate‐binding pocket. Drug susceptibility tests and growth curve analyses using an Escherichia coli recombinant expression system revealed that the hydrophilic patches of BpeB and BpeF are involved in the substrate specificity.