Adventures with ABC-proteins: highly conserved ATP-dependent transporters

The general properties of ABC transporters, from bacteria to humans, including a brief history of their initial discovery, are considered. ABC transporters, one of the largest protein super families and vital for human health, are in toto responsible for the transport of an enormous range of molecules from ions (CFTR) or anti-tumour drugs (Pgp/MDR) to large polypeptides. Nevertheless, all ABC transporters are powered by a conserved ATPase the ABC or NBD domain, using in all probability the same basic mechanism of action for the hydrolysis of ATP and its coupling to the transport process. Based on recent high resolution structures of several NBDs and an intact transporter, a model of how dimers of these important proteins function will be discussed, with particular attention to HlyB, the ABC transporter from E. coli.