2O9G

Crystal Structure of AqpZ mutant L170C complexed with mercury.


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.195 
  • R-Value Work: 0.166 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structural basis of aquaporin inhibition by mercury.

Savage, D.F.Stroud, R.M.

(2007) J.Mol.Biol. 368: 607-617

  • DOI: 10.1016/j.jmb.2007.02.070
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • The aquaporin family of channels was defined based on the inhibition of water transport by mercurial compounds. Despite the important role of mercurials, little is known about the structural changes involved upon mercury binding leading to channel in ...

    The aquaporin family of channels was defined based on the inhibition of water transport by mercurial compounds. Despite the important role of mercurials, little is known about the structural changes involved upon mercury binding leading to channel inhibition. To elucidate the mechanism we designed a mutant, T183C, of aquaporin Z (AqpZ) patterned after the known mercury-sensitive site of aquaporin 1 (AQP1) and determined the X-ray crystal structures of the unbound and mercury blocked states. Superposition of the two structures shows no conformational rearrangement upon mercury binding. In the blocked structure, there are two mercury sites, one bound to Cys183 and occluding the pore, and a second, also bound to the same cysteine but found buried in an interstitial cavity. To test the mechanism of blockade we designed a different mutant, L170C, to produce a more effective mercury block at the pore site. In a dose-response inhibition study, this mutant was 20 times more sensitive to mercury than wild-type AqpZ and four times more sensitive than T183C. The X-ray structure of L170C shows four mercury atoms at, or near, the pore site defined in the T183C structure and no structural change upon mercury binding. Thus, we elucidate a steric inhibition mechanism for this important class of channels by mercury.


    Organizational Affiliation

    Graduate Group in Biophysics, University of California at San Francisco, San Francisco, CA 94158, USA. savage@msg.ucsf.edu




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Aquaporin Z
A
234Escherichia coli (strain K12)Mutation(s): 3 
Gene Names: aqpZ (bniP)
Membrane protein
mpstruct
Group: 
TRANSMEMBRANE PROTEINS: ALPHA-HELICAL
Sub Group: 
Channels: Aquaporins and Glyceroporins
Protein: 
AqpZ aquaporin water channel
Find proteins for P60844 (Escherichia coli (strain K12))
Go to UniProtKB:  P60844
Small Molecules
Ligands 2 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
BOG
Query on BOG

Download SDF File 
Download CCD File 
A
B-OCTYLGLUCOSIDE
C14 H28 O6
HEGSGKPQLMEBJL-RKQHYHRCSA-N
 Ligand Interaction
HG
Query on HG

Download SDF File 
Download CCD File 
A
MERCURY (II) ION
Hg
BQPIGGFYSBELGY-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.195 
  • R-Value Work: 0.166 
  • Space Group: I 4
Unit Cell:
Length (Å)Angle (°)
a = 91.156α = 90.00
b = 91.156β = 90.00
c = 77.145γ = 90.00
Software Package:
Software NamePurpose
SCALAdata scaling
PHASERphasing
CCP4data scaling
REFMACrefinement
PDB_EXTRACTdata extraction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2007-02-13
    Type: Initial release
  • Version 1.1: 2008-05-01
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Derived calculations, Version format compliance