Researchers
have discovered that a cellular pump known to move drugs like antibiotics out of E. coli bacteria has the potential to
bring them in as well, opening new lines of research into combating the
bacteria.
Cells
must bring in and remove different materials to survive. To accomplish this,
they utilize different transporter proteins in their cell membranes, most of
which are powered by what is called the proton motive force. The proton motive
force is directed toward the inside of the cell in bacteria, which means that
protons naturally want to move in to the cell from the outside and do so if
there is a pathway for them. These transporters allow the measured movement of
protons into the cell -- and in exchange for protons moving in, drug molecules
get expelled.
It
was long thought that this coupled exchange of protons (in) and drugs (out) by
the transporter was very strict. However, in a new study researchers have found
that for E. coli's small multidrug
resistance transporter, called EmrE, proton and drug movements are not as
strictly coupled. This transporter can actually also move drugs and protons
across the membrane in the same direction, as well as the opposite direction --
introducing the option of moving molecules both into or out of the cell.
See:
Anne E. Robinson, Nathan E. Thomas, Emma A.
Morrison, Bryan M. Balthazor, Katherine A. Henzler-Wildman. New
free-exchange model of EmrE transport. Proceedings of the National
Academy of Sciences, 2017; 201708671 DOI: 10.1073/pnas.1708671114
Posted by Dr. Tim Sandle