3DET

Structure of the E148A, Y445A doubly ungated mutant of E.coli CLC_Ec1, Cl-/H+ antiporter


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.80 Å
  • R-Value Free: 0.299 
  • R-Value Work: 0.255 
  • R-Value Observed: 0.257 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history


Literature

Ion permeation through a Cl--selective channel designed from a CLC Cl-/H+ exchanger

Jayaram, H.Accardi, A.Wu, F.Williams, C.Miller, C.

(2008) Proc Natl Acad Sci U S A 105: 11194-11199

  • DOI: 10.1073/pnas.0804503105
  • Structures With Same Primary Citation

  • PubMed Abstract: 
  • The CLC family of Cl(-)-transporting proteins includes both Cl(-) channels and Cl(-)/H(+) exchange transporters. CLC-ec1, a structurally known bacterial homolog of the transporter subclass, exchanges two Cl(-) ions per proton with strict, obligatory ...

    The CLC family of Cl(-)-transporting proteins includes both Cl(-) channels and Cl(-)/H(+) exchange transporters. CLC-ec1, a structurally known bacterial homolog of the transporter subclass, exchanges two Cl(-) ions per proton with strict, obligatory stoichiometry. Point mutations at two residues, Glu(148) and Tyr(445), are known to impair H(+) movement while preserving Cl(-) transport. In the x-ray crystal structure of CLC-ec1, these residues form putative "gates" flanking an ion-binding region. In mutants with both of the gate-forming side chains reduced in size, H(+) transport is abolished, and unitary Cl(-) transport rates are greatly increased, well above values expected for transporter mechanisms. Cl(-) transport rates increase as side-chain volume at these positions is decreased. The crystal structure of a doubly ungated mutant shows a narrow conduit traversing the entire protein transmembrane width. These characteristics suggest that Cl(-) flux through uncoupled, ungated CLC-ec1 occurs via a channel-like electrodiffusion mechanism rather than an alternating-exposure conformational cycle that has been rendered proton-independent by the gate mutations.


    Organizational Affiliation

    Department of Biochemistry, Howard Hughes Medical Institute, Brandeis University, Waltham, MA 02454, USA.



Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
H(+)/Cl(-) exchange transporter clcAA, B473Escherichia coli K-12Mutation(s): 2 
Gene Names: clcAeriCyadQb0155JW5012
Find proteins for P37019 (Escherichia coli (strain K12))
Explore P37019 
Go to UniProtKB:  P37019
Protein Feature View
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  • Reference Sequence

Find similar proteins by: Sequence  |  Structure

Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Fab fragment, Heavy chainC, E221Mus musculusMutation(s): 0 
Protein Feature View
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  • Reference Sequence

Find similar proteins by: Sequence  |  Structure

Entity ID: 3
MoleculeChainsSequence LengthOrganismDetails
Fab fragment, Light chainD, F211Mus musculusMutation(s): 0 
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.80 Å
  • R-Value Free: 0.299 
  • R-Value Work: 0.255 
  • R-Value Observed: 0.257 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 231.167α = 90
b = 97.514β = 132.88
c = 173.277γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
MAR345dtbdata collection
MOSFLMdata reduction
SCALAdata scaling
PHASERphasing

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2008-06-17
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2013-09-25
    Changes: Derived calculations
  • Version 1.3: 2014-03-12
    Changes: Structure summary