Efflux pump

[1] The efflux could also be the movement of heavy metals, organic pollutants, plant-produced compounds, quorum sensing signals, bacterial metabolites and neurotransmitters.

Bacterial efflux pumps are classified into five major superfamilies, based on their amino acid sequence and the energy source used to export their substrates: Of these, only the ABC superfamily are primary transporters, the rest being secondary transporters utilizing proton or sodium gradient as a source of energy.

Examples include: The ability of efflux systems to recognize a large number of compounds other than their natural substrates is probably because substrate recognition is based on physicochemical properties, such as hydrophobicity, aromaticity and ionizable character rather than on defined chemical properties, as in classical enzyme-substrate or ligand-receptor recognition.

Because most antibiotics are amphiphilic molecules - possessing both hydrophilic and hydrophobic characters - they are easily recognized by many efflux pumps.

Verapamil, for example, is used to block P-glycoprotein-mediated efflux of DNA-binding fluorophores, thereby facilitating fluorescent cell sorting for DNA content.

Various natural products have been shown to inhibit bacterial efflux pumps including the carotenoids capsanthin and capsorubin,[19] the flavonoids rotenone and chrysin,[19] and the alkaloid lysergol.