Multidrug ABC transporters in bacteria

Multidrug efflux transporters are a plague in the antibiotic resistance mechanisms as they confer the capacity of bacteria to evade most of current therapies. Although these transporters were initially discovered as proton-motive driven pumps, another class of multidrug efflux transporters has emerged in the mid-90s that are powered by ATP hydrolysis. This new class of transporters belongs to one of the largest families of proteins, the ATP-Binding Cassette (ABC) transporters, which are involved in the influx or efflux of a huge variety of molecules. Tremendous progresses have been made in the recent years regarding the functioning mechanism of multidrug efflux ABC transporters, in particular with the accumulation of 3D structures, but many questions remain unsolved. In this review, we will give an overview of our current knowledge on the structure and function of multidrug ABC transporters with an emphasis on bacterial pumps.