2q69
From Proteopedia
| Line 1: | Line 1: | ||
[[Image:2q69.jpg|left|200px]] | [[Image:2q69.jpg|left|200px]] | ||
| - | + | <!-- | |
| - | + | The line below this paragraph, containing "STRUCTURE_2q69", creates the "Structure Box" on the page. | |
| - | + | You may change the PDB parameter (which sets the PDB file loaded into the applet) | |
| - | + | or the SCENE parameter (which sets the initial scene displayed when the page is loaded), | |
| - | + | or leave the SCENE parameter empty for the default display. | |
| - | + | --> | |
| - | | | + | {{STRUCTURE_2q69| PDB=2q69 | SCENE= }} |
| - | | | + | |
| - | + | ||
| - | }} | + | |
'''Crystal Structure of Nak channel D66N mutant''' | '''Crystal Structure of Nak channel D66N mutant''' | ||
| Line 28: | Line 25: | ||
[[Category: Jiang, Y.]] | [[Category: Jiang, Y.]] | ||
[[Category: Shi, N.]] | [[Category: Shi, N.]] | ||
| - | [[Category: | + | [[Category: Central cavity]] |
| - | [[Category: | + | [[Category: Helix bundle]] |
| - | [[Category: | + | [[Category: Inverted teepee]] |
| - | [[Category: | + | [[Category: Ion binding]] |
| - | [[Category: | + | [[Category: Membrane protein]] |
| - | [[Category: | + | [[Category: Metal transport]] |
| - | [[Category: | + | [[Category: Tetramer]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun May 4 14:25:34 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 11:25, 4 May 2008
Crystal Structure of Nak channel D66N mutant
Overview
Apparent blockage of monovalent cation currents by the permeating blocker Ca(2+) is a physiologically essential phenomenon relevant to cyclic nucleotide-gated (CNG) channels. The recently determined crystal structure of a bacterial homolog of CNG channel pores, the NaK channel, revealed a Ca(2+) binding site at the extracellular entrance to the selectivity filter. This site is not formed by the side-chain carboxylate groups from the conserved acidic residue, Asp-66 in NaK, conventionally thought to directly chelate Ca(2+) in CNG channels, but rather by the backbone carbonyl groups of residue Gly-67. Here we present a detailed structural analysis of the NaK channel with a focus on Ca(2+) permeability and blockage. Our results confirm that the Asp-66 residue, although not involved in direct chelation of Ca(2+), plays an essential role in external Ca(2+) binding. Furthermore, we give evidence for the presence of a second Ca(2+) binding site within the NaK selectivity filter where monovalent cations also bind, providing a structural basis for Ca(2+) permeation through the NaK pore. Compared with other Ca(2+)-binding proteins, both sites in NaK present a novel mode of Ca(2+) chelation, using only backbone carbonyl oxygen atoms from residues in the selectivity filter. The external site is under indirect control by an acidic residue (Asp-66), making it Ca(2+)-specific. These findings give us a glimpse of the possible underlying mechanisms allowing Ca(2+) to act both as a permeating ion and blocker of CNG channels and raise the possibility of a similar chemistry governing Ca(2+) chelation in Ca(2+) channels.
About this Structure
2Q69 is a Single protein structure of sequence from Bacillus cereus. Full crystallographic information is available from OCA.
Reference
Structural insight into Ca2+ specificity in tetrameric cation channels., Alam A, Shi N, Jiang Y, Proc Natl Acad Sci U S A. 2007 Sep 25;104(39):15334-9. Epub 2007 Sep 18. PMID:17878296 Page seeded by OCA on Sun May 4 14:25:34 2008
