3EJZ

Structure of E203V mutant E.coli Cl-/H+ exchanger, CLC-ec1


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.90 Å
  • R-Value Free: 0.281 
  • R-Value Work: 0.252 
  • R-Value Observed: 0.253 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Intracellular proton-transfer mutants in a CLC Cl-/H+ exchanger.

Lim, H.H.Miller, C.

(2009) J Gen Physiol 133: 131-138

  • DOI: 10.1085/jgp.200810112
  • Primary Citation of Related Structures:  
    3EJY, 3EJZ

  • PubMed Abstract: 
  • CLC-ec1, a bacterial homologue of the CLC family's transporter subclass, catalyzes transmembrane exchange of Cl(-) and H(+). Mutational analysis based on the known structure reveals several key residues required for coupling H(+) to the stoichiometric countermovement of Cl(-) ...

    CLC-ec1, a bacterial homologue of the CLC family's transporter subclass, catalyzes transmembrane exchange of Cl(-) and H(+). Mutational analysis based on the known structure reveals several key residues required for coupling H(+) to the stoichiometric countermovement of Cl(-). E148 (Glu(ex)) transfers protons between extracellular water and the protein interior, and E203 (Glu(in)) is thought to function analogously on the intracellular face of the protein. Mutation of either residue eliminates H(+) transport while preserving Cl(-) transport. We tested the role of Glu(in) by examining structural and functional properties of mutants at this position. Certain dissociable side chains (E, D, H, K, R, but not C and Y) retain H(+)/Cl(-) exchanger activity to varying degrees, while other mutations (V, I, or C) abolish H(+) coupling and severely inhibit Cl(-) flux. Transporters substituted with other nonprotonatable side chains (Q, S, and A) show highly impaired H(+) transport with substantial Cl(-) transport. Influence on H(+) transport of side chain length and acidity was assessed using a single-cysteine mutant to introduce non-natural side chains. Crystal structures of both coupled (E203H) and uncoupled (E203V) mutants are similar to wild type. The results support the idea that Glu(in) is the internal proton-transfer residue that delivers protons from intracellular solution to the protein interior, where they couple to Cl(-) movements to bring about Cl(-)/H(+) exchange.


    Organizational Affiliation

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



Macromolecules
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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
H(+)/Cl(-) exchange transporter clcA AB473Escherichia coliMutation(s): 1 
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
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Entity ID: 2
MoleculeChainsSequence LengthOrganismDetailsImage
Fab fragment, Heavy chain CE221Mus musculusMutation(s): 0 
Protein Feature View
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  • Reference Sequence
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Entity ID: 3
MoleculeChainsSequence LengthOrganismDetailsImage
Fab fragment, Light chain DF211Mus musculusMutation(s): 0 
Gene Names: Igkc
Find proteins for P01837 (Mus musculus)
Explore P01837 
Go to UniProtKB:  P01837
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.90 Å
  • R-Value Free: 0.281 
  • R-Value Work: 0.252 
  • R-Value Observed: 0.253 
  • Space Group: C 1 2 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 231.259α = 90
b = 96.415β = 131.78
c = 170.15γ = 90
Software Package:
Software NamePurpose
CBASSdata collection
PHASERphasing
REFMACrefinement
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

  • Deposited Date: 2008-09-18 
  • Released Date: 2009-02-17 
  • Deposition Author(s): Lim, H.-H., Miller, C.

Revision History  (Full details and data files)

  • Version 1.0: 2009-02-17
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2013-09-18
    Changes: Derived calculations