6BGJ

Cryo-EM structure of the TMEM16A calcium-activated chloride channel in LMNG


Experimental Data Snapshot

  • Method: ELECTRON MICROSCOPY
  • Resolution: 3.8 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 

wwPDB Validation 3D Report Full Report


This is version 1.4 of the entry. See complete history

Literature

Cryo-EM structures of the TMEM16A calcium-activated chloride channel.

Dang, S.Feng, S.Tien, J.Peters, C.J.Bulkley, D.Lolicato, M.Zhao, J.Zuberbuhler, K.Ye, W.Qi, L.Chen, T.Craik, C.S.Nung Jan, Y.Minor, D.L.Cheng, Y.Yeh Jan, L.

(2017) Nature 552: 426-429

  • DOI: 10.1038/nature25024
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Calcium-activated chloride channels (CaCCs) encoded by TMEM16A control neuronal signalling, smooth muscle contraction, airway and exocrine gland secretion, and rhythmic movements of the gastrointestinal system. To understand how CaCCs mediate and con ...

    Calcium-activated chloride channels (CaCCs) encoded by TMEM16A control neuronal signalling, smooth muscle contraction, airway and exocrine gland secretion, and rhythmic movements of the gastrointestinal system. To understand how CaCCs mediate and control anion permeation to fulfil these physiological functions, knowledge of the mammalian TMEM16A structure and identification of its pore-lining residues are essential. TMEM16A forms a dimer with two pores. Previous CaCC structural analyses have relied on homology modelling of a homologue (nhTMEM16) from the fungus Nectria haematococca that functions primarily as a lipid scramblase, as well as subnanometre-resolution electron cryo-microscopy. Here we present de novo atomic structures of the transmembrane domains of mouse TMEM16A in nanodiscs and in lauryl maltose neopentyl glycol as determined by single-particle electron cryo-microscopy. These structures reveal the ion permeation pore and represent different functional states. The structure in lauryl maltose neopentyl glycol has one Ca 2+ ion resolved within each monomer with a constricted pore; this is likely to correspond to a closed state, because a CaCC with a single Ca 2+ occupancy requires membrane depolarization in order to open (C.J.P. et al., manuscript submitted). The structure in nanodiscs has two Ca 2+ ions per monomer and its pore is in a closed conformation; this probably reflects channel rundown, which is the gradual loss of channel activity that follows prolonged CaCC activation in 1 mM Ca 2+ . Our mutagenesis and electrophysiological studies, prompted by analyses of the structures, identified ten residues distributed along the pore that interact with permeant anions and affect anion selectivity, as well as seven pore-lining residues that cluster near pore constrictions and regulate channel gating. Together, these results clarify the basis of CaCC anion conduction.


    Organizational Affiliation

    Department of Physiology, University of California, San Francisco, California 94158, USA.,Department of Biochemistry and Biophysics, University of California, San Francisco, California 94158, USA.,Molecular Biophysics and Integrated Bio-imaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.,Department of Pharmaceutical Chemistry, University of California, San Francisco, California 94158, USA.,Howard Hughes Medical Institute, University of California, San Francisco, California 94158, USA.,Department of Cellular and Molecular Pharmacology, University of California, San Francisco, California 94158, USA.,Cardiovascular Research Institute, University of California, San Francisco, California 94158, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Anoctamin-1
A, B
912Mus musculusMutation(s): 0 
Gene Names: Ano1 (Tmem16a)
Membrane protein
mpstruc
Group: 
TRANSMEMBRANE PROTEINS: ALPHA-HELICAL
Sub Group: 
TMEM16 Family Proteins
Protein: 
TMEM16A calcium-activated chloride channel
Find proteins for Q8BHY3 (Mus musculus)
Go to UniProtKB:  Q8BHY3
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CA
Query on CA

Download SDF File 
Download CCD File 
A, B
CALCIUM ION
Ca
BHPQYMZQTOCNFJ-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: ELECTRON MICROSCOPY
  • Resolution: 3.8 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 
Software Package:
Software NamePurpose
PHENIXrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute of General Medical SciencesUnited StatesR01GM098672
National Institutes of HealthUnited StatesS100D0020054
National Institutes of Health/National Institute of Neurological Disorders and StrokeUnited StatesR01NS069229
National Institutes of Health/National Institute of Neurological Disorders and StrokeUnited StatesR35NS097227
National Institutes of Health/National Heart, Lung, and Blood InstituteUnited StatesR01HL080050
National Institutes of Health/National Institute on Deafness and Other Communication DisordersUnited StatesR01DC007664
National Institutes of Health/National Cancer InstituteUnited StatesCA196276
National Institutes of Health/National Institute of General Medical SciencesUnited StatesGM111126
National Institutes of Health/National Institute on Drug AbuseUnited StatesK99DA041500

Revision History 

  • Version 1.0: 2017-12-27
    Type: Initial release
  • Version 1.1: 2018-01-10
    Type: Database references
  • Version 1.2: 2018-01-17
    Type: Author supporting evidence
  • Version 1.3: 2018-02-14
    Type: Other
  • Version 1.4: 2018-04-11
    Type: Data collection, Other, Structure summary