4LTP

Bacterial sodium channel in high calcium, I222 space group, crystal 2

Summary for 4LTP

• Entry DOI: 10.2210/pdb4ltp/pdb
• Related: 4LTO 4LTQ 4LTR
• Descriptor: Ion transport protein, CALCIUM ION (3 entities in total)
• Functional Keywords: cation channel fold, coiled coil sodium channel, plasma membrane, transport protein
• Biological source: Alkalilimnicola ehrlichii
• Total number of polymer chains: 4
• Total formula weight: 70133.92

Authors

Shaya, D.,Findeisen, F.,Abderemane-Ali, F.,Arrigoni, C.,Wong, S.,Reddy Nurva, S.,Loussouarn, G.,Minor, D.L. (deposition date: 2013-07-23, release date: 2013-10-23, Last modification date: 2023-09-20)

Primary citation

Shaya, D.,Findeisen, F.,Abderemane-Ali, F.,Arrigoni, C.,Wong, S.,Nurva, S.R.,Loussouarn, G.,Minor, D.L.
Structure of a prokaryotic sodium channel pore reveals essential gating elements and an outer ion binding site common to eukaryotic channels.
J.Mol.Biol., 426:467-483, 2014

PubMed Abstract: Voltage-gated sodium channels (NaVs) are central elements of cellular excitation. Notwithstanding advances from recent bacterial NaV (BacNaV) structures, key questions about gating and ion selectivity remain. Here, we present a closed conformation of NaVAe1p, a pore-only BacNaV derived from NaVAe1, a BacNaV from the arsenite oxidizer Alkalilimnicola ehrlichei found in Mono Lake, California, that provides insight into both fundamental properties. The structure reveals a pore domain in which the pore-lining S6 helix connects to a helical cytoplasmic tail. Electrophysiological studies of full-length BacNaVs show that two elements defined by the NaVAe1p structure, an S6 activation gate position and the cytoplasmic tail "neck", are central to BacNaV gating. The structure also reveals the selectivity filter ion entry site, termed the "outer ion" site. Comparison with mammalian voltage-gated calcium channel (CaV) selectivity filters, together with functional studies, shows that this site forms a previously unknown determinant of CaV high-affinity calcium binding. Our findings underscore commonalities between BacNaVs and eukaryotic voltage-gated channels and provide a framework for understanding gating and ion permeation in this superfamily.

PubMed: 24120938
DOI: 10.1016/j.jmb.2013.10.010

Experimental method

X-RAY DIFFRACTION (3.8 Å)