4ENE

Structure of the N- and C-terminal trimmed ClC-ec1 Cl-/H+ antiporter and Fab Complex


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.4 Å
  • R-Value Free: 0.278 
  • R-Value Work: 0.239 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Intracellular proton access in a cl(-)/h(+) antiporter.

Lim, H.H.Shane, T.Miller, C.

(2012) Plos Biol. 10: e1001441-e1001441

  • DOI: 10.1371/journal.pbio.1001441
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Chloride-transporting membrane proteins of the CLC family appear in two distinct mechanistic flavors: H(+)-gated Cl(-) channels and Cl(-)/H(+) antiporters. Transmembrane H(+) movement is an essential feature of both types of CLC. X-ray crystal struct ...

    Chloride-transporting membrane proteins of the CLC family appear in two distinct mechanistic flavors: H(+)-gated Cl(-) channels and Cl(-)/H(+) antiporters. Transmembrane H(+) movement is an essential feature of both types of CLC. X-ray crystal structures of CLC antiporters show the Cl(-) ion pathway through these proteins, but the H(+) pathway is known only inferentially by two conserved glutamate residues that act as way-stations for H(+) in its path through the protein. The extracellular-facing H(+) transfer glutamate becomes directly exposed to aqueous solution during the transport cycle, but the intracellular glutamate E203, Glu(in), is buried within the protein. Two regions, denoted "polar" and "interfacial," at the intracellular surface of the bacterial antiporter CLC-ec1 are examined here as possible pathways by which intracellular aqueous protons gain access to Glu(in). Mutations at multiple residues of the polar region have little effect on antiport rates. In contrast, mutation of E202, a conserved glutamate at the protein-water boundary of the interfacial region, leads to severe slowing of the Cl(-)/H(+) antiport rate. An X-ray crystal structure of E202Y, the most strongly inhibited of these substitutions, shows an aqueous portal leading to Glu(in) physically blocked by cross-subunit interactions; moreover, this mutation has only minimal effect on a monomeric CLC variant, which necessarily lacks such interactions. The several lines of experiments presented argue that E202 acts as a water-organizer that creates a proton conduit connecting intracellular solvent with Glu(in).


    Organizational Affiliation

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




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
H(+)/Cl(-) exchange transporter ClcA
A, B
446Escherichia coli (strain K12)Mutation(s): 0 
Gene Names: clcA (eriC, yadQ)
Membrane protein
mpstruct
Group: 
TRANSMEMBRANE PROTEINS: ALPHA-HELICAL
Sub Group: 
H+/Cl- or F- Exchange Transporters
Protein: 
H+/Cl- Exchange Transporter
Find proteins for P37019 (Escherichia coli (strain K12))
Go to UniProtKB:  P37019
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
heavy chain of Fab fragment
C, E
222N/AMutation(s): 0 
Protein Feature View is not available: No corresponding UniProt sequence found.
Entity ID: 3
MoleculeChainsSequence LengthOrganismDetails
light chain of Fab fragment
D, F
211N/AMutation(s): 0 
Protein Feature View is not available: No corresponding UniProt sequence found.
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
MAL
Query on MAL

Download SDF File 
Download CCD File 
B
MALTOSE
C12 H22 O11
GUBGYTABKSRVRQ-ASMJPISFSA-N
 Ligand Interaction
DMU
Query on DMU

Download SDF File 
Download CCD File 
A, B
DECYL-BETA-D-MALTOPYRANOSIDE
DECYLMALTOSIDE
C22 H42 O11
WOQQAWHSKSSAGF-WXFJLFHKSA-N
 Ligand Interaction
CL
Query on CL

Download SDF File 
Download CCD File 
A, B
CHLORIDE ION
Cl
VEXZGXHMUGYJMC-UHFFFAOYSA-M
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.4 Å
  • R-Value Free: 0.278 
  • R-Value Work: 0.239 
  • Space Group: C 1 2 1
Unit Cell:
Length (Å)Angle (°)
a = 232.260α = 90.00
b = 97.520β = 132.87
c = 173.960γ = 90.00
Software Package:
Software NamePurpose
ADSCdata collection
PHASERphasing
MOSFLMdata reduction
SCALAdata scaling
PHENIXrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2012-12-26
    Type: Initial release
  • Version 1.1: 2018-01-24
    Type: Structure summary