ABC transporter: Difference between revisions

'''A'''TP '''B'''inding '''C'''assette (ABC) '''[[Transporters]]''' are ATP-dependent membrane proteins critical for most aspects of cell physiology, including the uptake of nutrients (importers) and elimination of waste products and energy generation (exporters) which are predominantly expressed in excretory organs, such as the liver, intestine, blood-brain barrier, blood-testes barrier, placenta, and kidney<ref name="Kidney"/><ref name="FourDomainsABCT"/>. There are many ABC Transporters in organisms, for instance, there are 28 in yeast,58 in ''Caenorhabditis'', 51 in ''Drosophila'',129 in ''Arabadopsis'',and the 69 ABC transporters in ''E. coli'' account for almost 5% of its genomic coding capacity<ref name="EColi"/>. ABC transporter protein translocates substrates across membranes.  It contains a Solute Binding Domain (SBD).  '''CFTR''' (Cystic Fibrosis Transmembrane Regulator)  translocates chloride and  thiocyanate.  It contains a nucleotide binding domain (NBD).  Mutations in CFTR lead to Cystic Fibrosis. In humans the ABC transporters are classified into subfamilies, i.e. ABCB6 is ABC subfamily B member 6.  ABC Transporters have two main functionalities acting either as exporters or importers. '''ABC ''Exporters''''' release bound drugs to the extracellular environment, while '''ABC ''Importers''''' accept substrate molecules from their relevant substrate-binding proteins<ref name="biochembook"/>. For instance the Vitamin B12 transporter BtuCD (PDB [[1l7v]]) is a binding protein-dependent ABC transporter system that uses the power of ATP hydrolysis to pump vitamin B12 into the cytoplasm of E. coli<ref name="BtuCD-Ecoli"/>. <br />

== Structural highlights ==