mrx

ATP-binding cassette super-family G member 2 is a protein that in humans is encoded by the ABCG2 gene. ABCG2 has also been designated as CDw338 (cluster of differentiation w338). ABCG2 is a translocation protein used to actively pump drugs and other compounds against their concentration gradient using the bonding and hydrolysis of ATP as the energy source.
ABCG2 forms into a homodimer to assume its active transport conformation. The dimer weighs approximately 144 kDa. The expression of this transport protein is highly conserved throughout the animal kingdom, pointing to its importance.
Substrate binding with compounds occurs in the large central cavity. ABCG2 can bind to a broad range of compounds but binds strongest to flat, polycyclic chemicals with lots of hydrophobic character.