Hot on the Trail of Metabolic Diseases and Resistance to Antibiotics

Photo: Detailed side-view of “TM287/288”

Detailed side-view of “TM287/288”.
The transporter adopts is
inward-facing state. The two
different protein chains are
marked in turquoise and pink;
© University of Zurich

membrane. Over 40 different ABC transporters perform vital functions in humans. Genetic defects in ABC transporters can trigger metabolic diseases such as gout, neonatal diabetes or cystic fibrosis, and certain ABC transporters also cause resistance to a wide range of drugs. In tumor cells, increased amounts of ABC transporters that pump chemotherapeutic substances out of the cell are often produced, thus rendering anticancer drugs ineffective. Analogous mechanisms play a key role in many pathogenic bacteria: ABC transporters carry antibiotics out of the cell – multi-resistant bacteria are the result.

Despite their major importance in biology and medicine, so far the atomic structure of only a few ABC transporters has been decoded. Now, under the supervision of Markus Seeger and Professor Markus Grütter, scientists have succeeded in cracking the atomic structure of the new ABC transporter “TM287/288”.

The membrane protein originates from a thermophilic bacterium. Compared to structures already known, “TM287/288” has two different protein chains that assemble into a heterodimer. About half of the 40 human ABC transporters are heterodimers. “The asymmetries discovered enable us to consider the role of ABC transporters in a new light,” explains Seeger. “In the longer term, our results could help develop new medication against multi-resistant bacteria or tumors that are difficult to treat. They also make new approaches to curing or alleviating hereditary diseases possible,” says Grütter.

MEDICA.de; Source: University of Zurich