Microbiology Animation 8.4 ABC Transporters

This opens up the cytoplasmic side to allow the solute to enter the cell.

ADP, an inorganic phosphate, are released and the transporter returns to its resting state.

A system that takes in a particular nutrient or solute uses a solute binding protein to grab the solute.

Either as it floats by a gram positive microbe or as the molecule enters the periplasm of a gram negative cell.

There are two main types of ABC transporters.

Influx and efflux

The energy stored in ATP can drive membrane transport of nutrients into the cell.

The largest family of energy driven transport systems are the ABC transporters. They are named for their ATP binding cassettes. These are also called nucleotide binding domains.

On receiving the signal, the nucleotide binding protein hydrolyze ATP

and send another conformational change through the channel.

The solute binding protein

directs the solute to the periplasmic face of the channel protein.

Efflux ABC transporters include multidrug pumps that

drive out antibiotics and toxins.

Solute binding proteins have a high affinity for their matched solutes

so their use increases the efficiency of transport when concentrations of the solute are low.

Influx ABC transporters carry critical nutrients such as

sugars and amino acids

The interaction with the channel protein triggers a structural change in the channel protein

that is telegraph to the ATP binding cassettes.