3OGC
KcsA E71A variant in presence of Na+
Summary for 3OGC
| Entry DOI | 10.2210/pdb3ogc/pdb |
| Descriptor | antibody Fab fragment heavy chain, antibody Fab fragment light chain, Voltage-gated potassium channel, ... (4 entities in total) |
| Functional Keywords | voltage-gated channel, antibody fab complex, membrane protein |
| Biological source | Mus musculus (mouse) More |
| Cellular location | Cell membrane; Multi-pass membrane protein: P0A334 |
| Total number of polymer chains | 3 |
| Total formula weight | 60998.52 |
| Authors | McCoy, J.G.,Nimigean, C.M. (deposition date: 2010-08-16, release date: 2011-03-16, Last modification date: 2024-11-27) |
| Primary citation | Cheng, W.W.,McCoy, J.G.,Thompson, A.N.,Nichols, C.G.,Nimigean, C.M. Mechanism for selectivity-inactivation coupling in KcsA potassium channels. Proc.Natl.Acad.Sci.USA, 108:5272-5277, 2011 Cited by PubMed Abstract: Structures of the prokaryotic K(+) channel, KcsA, highlight the role of the selectivity filter carbonyls from the GYG signature sequence in determining a highly selective pore, but channels displaying this sequence vary widely in their cation selectivity. Furthermore, variable selectivity can be found within the same channel during a process called C-type inactivation. We investigated the mechanism for changes in selectivity associated with inactivation in a model K(+) channel, KcsA. We found that E71A, a noninactivating KcsA mutant in which a hydrogen-bond behind the selectivity filter is disrupted, also displays decreased K(+) selectivity. In E71A channels, Na(+) permeates at higher rates as seen with and flux measurements and analysis of intracellular Na(+) block. Crystal structures of E71A reveal that the selectivity filter no longer assumes the "collapsed," presumed inactivated, conformation in low K(+), but a "flipped" conformation, that is also observed in high K(+), high Na(+), and even Na(+) only conditions. The data reveal the importance of the E71-D80 interaction in both favoring inactivation and maintaining high K(+) selectivity. We propose a molecular mechanism by which inactivation and K(+) selectivity are linked, a mechanism that may also be at work in other channels containing the canonical GYG signature sequence. PubMed: 21402935DOI: 10.1073/pnas.1014186108 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (3.8 Å) |
Structure validation
Download full validation report
