KcsA (K channel of streptomyces A) is a prokaryotic potassium channel from the soil bacterium Streptomyces lividans that has been studied extensively in ion channel research. The pH activated protein possesses two transmembrane segments and a highly selective pore region, responsible for the gating and shuttling of K+ ions out of the cell. The amino acid sequence found in the selectivity filter of KcsA is highly conserved among both prokaryotic and eukaryotic K+ voltage channels, as a result, research on KcsA has provided important structural and mechanistic insight on the molecular basis for K+ ion selection and conduction. As one of the most studied ion channels to this day, KcsA is a template for research on K+ channel function and its elucidated structure underlies computational modeling of channel dynamics for both prokaryotic and eukaryotic species. KcsA was the first potassium ion channel to be characterized using x-ray crystallography by Roderick MacKinnon and his colleagues in 1998. In the years leading up to this, research on the structure of K+ channels was centered on the use of small toxin binding to reveal the location of the pore and selectivity filter among channel residues. MacKinnon’s group theorized the tetrameric arrangement of the transmembrane segments, and even suggested presence of pore-forming “loops” in the filter region made of short segments of amino acids that interacted with K+ ions passing through the channel. To study its function, several mutants have been produced. Here you can see a very recent structure of the KcsA channel in complex with Barium (greeen central sphere), determined by X-ray crystallography (PDB code: 7MJT)
#molecularart ... #immolecular ... #channel ... #KcsA ... #potassium ... #barium ... #mutant ... #transport ... #bacteria ... #xray
Structure of the KcsA channel rendered with @proteinimaging and depicted with @corelphotopaint
#molecularart ... #immolecular ... #channel ... #KcsA ... #potassium ... #barium ... #mutant ... #transport ... #bacteria ... #xray
Structure of the KcsA channel rendered with @proteinimaging and depicted with @corelphotopaint
