# Small Molecule Inhibition of a Multidrug Efflux Pump of Pseudomonas aeruginosa

> **NIH NIH R03** · UNIVERSITY OF OKLAHOMA · 2021 · $70,563

## Abstract

Project summary/Abstract
Small Molecule Inhibition of a Multidrug Efflux Pump of Pseudomonas aeruginosa
Multidrug resistance (MDR) is a major global threat to the public health and has posed an economic burden
worldwide. Each year, more than 2.8 million antibiotic-resistant infections occur in the U.S. alone, causing around
36,000 deaths. Resistant bacteria have evolved with both intrinsic and acquired resistance mechanisms to
protect, escape and avoid antibiotics, causing inefficacy of almost all available antibiotics. One of the important
pathogens classified as an urgent threat to public health is Pseudomonas aeruginosa (P. aeruginosa). MDR
strains of Pseudomonas are resistant to nearly all available antibiotics and thus identified as a serious threat by
the Centers for Disease Control and Prevention. The primary cause for multidrug resistance in Gram-negative
bacteria including P. aeruginosa is overexpression of resistance-nodulation-cell division (RND) family multidrug
efflux pumps by exporting drug molecules out of the cells. Therefore, inhibition of multidrug efflux pumps by
efflux pump inhibitors (EPIs), is an attractive and promising approach to potentiate and revive antibacterial
activities of existing antibiotics by synergizing or inhibiting efflux pumps of resistant bacteria. However, better
understanding of drug efflux and efflux inhibition by EPIs is essential to develop novel and potent
EPIs/antibacterials with better permeation and efflux inhibition. So, the goal of the proposed research is to identify
potent inhibitors of MexEF-OprN, a multidrug efflux pump of P. aeruginosa and understand the biochemical
mechanisms of drug efflux and efflux inhibition. We will use an interdisciplinary approach, including
microbiological, biochemical, biophysical, cell-based assays and in vitro functional assays. We will map the drug
binding and efflux inhibition site(s) of the efflux pump transporter. Specifically, we will identify the specific amino-
acid residues of efflux pump drug transporter essential for drug binding, efflux, and efflux inhibition using a
combinatorial unbiased approach of directed evolution and cell-based assays. We will also measure the
specificity of inhibitors and/or substrates using both biophysical and in vitro functional assays. We will use a
powerful biophysical tool, Surface Plasmon Resonance (SPR) to determine the direct binding, specificity and
affinity of substrates and inhibitors for MexF efflux pump transporter. We will measure the kinetics of small-
molecule interactions with MexF to determine their affinity using purified MexF efflux pump using a real-time in
vitro PLs-based transport assay.

## Key facts

- **NIH application ID:** 10286575
- **Project number:** 1R03AI163845-01
- **Recipient organization:** UNIVERSITY OF OKLAHOMA
- **Principal Investigator:** HELEN I ZGURSKAYA
- **Activity code:** R03 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $70,563
- **Award type:** 1
- **Project period:** 2021-06-21 → 2023-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10286575

## Citation

> US National Institutes of Health, RePORTER application 10286575, Small Molecule Inhibition of a Multidrug Efflux Pump of Pseudomonas aeruginosa (1R03AI163845-01). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10286575. Licensed CC0.

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