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.