Identification of a bacterial NCS1 family transporter enabling high-affinity uptake of the antidiabetic drug metformin.
Xu Z-J, Li T, Zhou N-Y
Phytoremediation
Metformin from millions of daily prescriptions is seeping into the water your garden draws from — and now we know which bacteria can eat it and how, opening a path toward engineered microbial cleanup of pharmaceutical-polluted soil and irrigation water.
A common diabetes medication called metformin doesn't fully break down in wastewater treatment and ends up in rivers, soil, and groundwater. Researchers found a soil bacterium with a special doorway protein that lets it pull metformin inside the cell and digest it. Understanding this protein could help scientists use bacteria to clean up pharmaceutical pollution in water and soil before it reaches the plants and ecosystems we depend on.
Key Findings
The discovered transporter (MetT) binds metformin with a Km of 15.90 µM — roughly 100-fold higher affinity than the human equivalent, meaning bacteria can scavenge metformin even at very low environmental concentrations.
Knocking out the metT gene completely stopped the bacterium from growing on metformin, proving the transporter is the essential gateway before any degradation can occur.
Structural modeling showed the binding pocket is lined with aromatic amino acids that grip metformin via cation-π interactions — a distinct recognition mechanism not seen in previously characterized transporters of this family.
chevron_right Technical Summary
Scientists discovered a bacterial protein that efficiently absorbs metformin — the world's most prescribed diabetes drug — allowing soil and water bacteria to break it down. This finding explains how microbes degrade a pharmaceutical that has become a widespread environmental pollutant in rivers, groundwater, and agricultural soils.
Abstract Preview
Metformin is a first-line antidiabetic medication for type 2 diabetes and a widely dispersed emerging pollutant in aquatic systems. During medication, its strong positive charge (pKa = 12.4) unde...
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