1bl8 | pdb_00001bl8

POTASSIUM CHANNEL (KCSA) FROM STREPTOMYCES LIVIDANS

spinqualitylabelsall models 1bl8, resolution 3.20Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 1bl8 is a 4 chain structure with sequence from "actinomyces_lividans"_krasil'nikov_et_al._1965 "actinomyces lividans" krasil'nikov et al. 1965. The February 2003 RCSB PDB Molecule of the Month feature on Potassium Channels by Shuchismita Dutta and David S. Goodsell is 10.2210/rcsb_pdb/mom_2003_2. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: K Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum Function [KCSA_STRLI] Acts as a pH-gated potassium ion channel; changing the cytosolic pH from 7 to 4 opens the channel, although it is not clear if this is the physiological stimulus for channel opening. Monovalent cation preference is K(+) > Rb(+) > NH4(+) >> Na(+) > Li(+). Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed The potassium channel from Streptomyces lividans is an integral membrane protein with sequence similarity to all known K+ channels, particularly in the pore region. X-ray analysis with data to 3.2 angstroms reveals that four identical subunits create an inverted teepee, or cone, cradling the selectivity filter of the pore in its outer end. The narrow selectivity filter is only 12 angstroms long, whereas the remainder of the pore is wider and lined with hydrophobic amino acids. A large water-filled cavity and helix dipoles are positioned so as to overcome electrostatic destabilization of an ion in the pore at the center of the bilayer. Main chain carbonyl oxygen atoms from the K+ channel signature sequence line the selectivity filter, which is held open by structural constraints to coordinate K+ ions but not smaller Na+ ions. The selectivity filter contains two K+ ions about 7.5 angstroms apart. This configuration promotes ion conduction by exploiting electrostatic repulsive forces to overcome attractive forces between K+ ions and the selectivity filter. The architecture of the pore establishes the physical principles underlying selective K+ conduction. The structure of the potassium channel: molecular basis of K+ conduction and selectivity.,Doyle DA, Morais Cabral J, Pfuetzner RA, Kuo A, Gulbis JM, Cohen SL, Chait BT, MacKinnon R Science. 1998 Apr 3;280(5360):69-77. PMID:9525859 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Amino Acids Cation-pi interactions Glutamate receptor (GluA2) Nobel Prizes for 3D Molecular Structure Potassium Channel Practical Guide to Homology Modeling User:Eric Martz/Introduction to Structural Bioinformatics I

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