The structural basis of substrate promiscuity within the small multidrug resistance family

Abstract

The Small Multidrug Resistance (SMR) family of membrane proteins is known for conferring resistance to a wide range of antibiotics and xenobiotic compounds in bacteria. Moreover, their small size and rare dual topology architecture have made them a suitable model system for studying membrane proteins’ mechanism and evolution. We recently characterized a new subtype within this family, comprised of guanidinium exporters or Gdx proteins. Gdx proteins facilitate the transport of chemical compounds with guanidinyl moieties and share an overlapping substrate specificity with drug exporter subtype (QAC).