PDBsum entry 7b5c

Membrane protein

PDB id: 7b5c

Contents

Protein chains

718 a.a.

Metals

_CA ×4

PDB id:

7b5c

Name:

Membrane protein

Title:

Structure of calcium-bound mtmem16a(ac) chloride channel at 3.7 a resolution

Structure:

Anoctamin-1. Chain: a, b. Synonym: transmembrane protein 16a. Engineered: yes

Source:

Mus musculus. Mouse. Organism_taxid: 10090. Gene: ano1, tmem16a. Expressed in: homo sapiens. Expression_system_taxid: 9606

Authors:

A.K.M.Lam,J.Rheinberger,C.Paulino,R.Dutzler

Key ref:

A.K.M.Lam et al. (2021). Gating the pore of the calcium-activated chloride channel TMEM16A. Nat Commun, 12, 785. PubMed id: 33542223 DOI: 10.1016/S0263-7855(97)00009-X

Date:

03-Dec-20 Release date: 10-Feb-21

Protein chains

Q8BHY3  (ANO1_MOUSE) -  Anoctamin-1 from Mus musculus

Seq: 960 a.a.

Struc: 718 a.a.

DOI no: 10.1016/S0263-7855(97)00009-X

Nat Commun 12:785 (2021)

PubMed id: 33542223

Gating the pore of the calcium-activated chloride channel TMEM16A.

A.K.M.Lam, J.Rheinberger, C.Paulino, R.Dutzler.

ABSTRACT

The binding of cytoplasmic Ca²⁺ to the anion-selective channel TMEM16A triggers a conformational change around its binding site that is coupled to the release of a gate at the constricted neck of an hourglass-shaped pore. By combining mutagenesis, electrophysiology, and cryo-electron microscopy, we identified three hydrophobic residues at the intracellular entrance of the neck as constituents of this gate. Mutation of each of these residues increases the potency of Ca²⁺ and results in pronounced basal activity. The structure of an activating mutant shows a conformational change of an α-helix that contributes to Ca²⁺ binding as a likely cause for the basal activity. Although not in physical contact, the three residues are functionally coupled to collectively contribute to the stabilization of the gate in the closed conformation of the pore, thus explaining the low open probability of the channel in the absence of Ca²⁺.