5cbh

Publication Abstract from PubMed

The selectivity filter is an essential functional element of K(+) channels that is highly conserved both in terms of its primary sequence and its three-dimensional structure. Here, we investigate the properties of an ion channel from the Gram-positive bacterium Tsukamurella paurometabola with a selectivity filter formed by an uncommon proline-rich sequence. Electrophysiological recordings show that it is a non-selective cation channel and that its activity depends on Ca(2+) concentration. In the crystal structure, the selectivity filter adopts a novel conformation with Ca(2+) ions bound within the filter near the pore helix where they are coordinated by backbone oxygen atoms, a recurrent motif found in multiple proteins. The binding of Ca(2+) ion in the selectivity filter controls the widening of the pore as shown in crystal structures and in molecular dynamics simulations. The structural, functional and computational data provide a characterization of this calcium-gated cationic channel.

Structural and functional characterization of a calcium-activated cation channel from Tsukamurella paurometabola.,Dhakshnamoorthy B, Rohaim A, Rui H, Blachowicz L, Roux B Nat Commun. 2016 Sep 28;7:12753. doi: 10.1038/ncomms12753. PMID:27678077^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.