5ERA
Human Connexin-26 (Calcium-free)
Summary for 5ERA
| Entry DOI | 10.2210/pdb5era/pdb |
| Related | 5ER7 |
| Descriptor | Gap junction beta-2 protein (1 entity in total) |
| Functional Keywords | gap junction, ion channel, calcium binding, electrostatic gating, calcium binding protein |
| Biological source | Homo sapiens (Human) |
| Cellular location | Cell membrane; Multi-pass membrane protein: P29033 |
| Total number of polymer chains | 2 |
| Total formula weight | 52277.70 |
| Authors | Purdy, M.D.,Bennett, B.C.,Baker, K.A.,Yeager, M.J. (deposition date: 2015-11-13, release date: 2016-01-27, Last modification date: 2024-10-23) |
| Primary citation | Bennett, B.C.,Purdy, M.D.,Baker, K.A.,Acharya, C.,McIntire, W.E.,Stevens, R.C.,Zhang, Q.,Harris, A.L.,Abagyan, R.,Yeager, M. An electrostatic mechanism for Ca(2+)-mediated regulation of gap junction channels. Nat Commun, 7:8770-8770, 2016 Cited by PubMed Abstract: Gap junction channels mediate intercellular signalling that is crucial in tissue development, homeostasis and pathologic states such as cardiac arrhythmias, cancer and trauma. To explore the mechanism by which Ca(2+) blocks intercellular communication during tissue injury, we determined the X-ray crystal structures of the human Cx26 gap junction channel with and without bound Ca(2+). The two structures were nearly identical, ruling out both a large-scale structural change and a local steric constriction of the pore. Ca(2+) coordination sites reside at the interfaces between adjacent subunits, near the entrance to the extracellular gap, where local, side chain conformational rearrangements enable Ca(2+)chelation. Computational analysis revealed that Ca(2+)-binding generates a positive electrostatic barrier that substantially inhibits permeation of cations such as K(+) into the pore. Our results provide structural evidence for a unique mechanism of channel regulation: ionic conduction block via an electrostatic barrier rather than steric occlusion of the channel pore. PubMed: 26753910DOI: 10.1038/ncomms9770 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (3.8 Å) |
Structure validation
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