1PQ4

Crystal structure of ZnuA


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.209 
  • R-Value Work: 0.172 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structural Determinants of Metal Specificity in the Zinc Transport Protein ZnuA from Synechocystis 6803.

Banerjee, S.Wei, B.Bhattacharyya-Pakrasi, M.Pakrasi, H.B.Smith, T.J.

(2003) J.Mol.Biol. 333: 1061-1069


  • PubMed Abstract: 
  • A number of bacterial metal transporters belong to the cluster 9 family of ABC transporters. The residues in the periplasmic domain thought to be involved in metal binding seem highly conserved and yet the transporters have varying metal specificity. ...

    A number of bacterial metal transporters belong to the cluster 9 family of ABC transporters. The residues in the periplasmic domain thought to be involved in metal binding seem highly conserved and yet the transporters have varying metal specificity. To solve this seeming paradox and ascertain how metal specificity is exacted, the structure of ZnuA, the periplasmic domain of a zinc transporter from Synechocystis 6803, has been determined to a resolution of 1.9A. In previously determined structures of homologous proteins, four residues chelate the bound metal. From sequence alignments of the cluster 9 metal transporters, the fourth residue in this metal-binding site, an aspartate, is also present in the appropriate position in the ZnuA sequence. However, this result is misleading, since our structural data indicate that zinc binds via only three histidine residues and the aspartate is replaced by a large hydrophobic cavity. We propose that ZnuA binds zinc over manganese by providing only three ligating residues. ZnuA has a highly charged and mobile loop that protrudes from the protein in the vicinity of the metal-binding site. Similar loops are found in other types of zinc transporters but not manganese transporters. Therefore, we propose that the function of this domain is to act as a zinc chaperone to facilitate acquisition. Therefore, while Mn2+ transporters can bind Zn2+ in vitro they may not be able to acquire it in vivo without this structure because of the low concentration of free Zn2+.


    Organizational Affiliation

    Donald Danforth Plant Science Center, 975 North Warson Road, St Louis, MO 63132, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
periplasmic binding protein component of an ABC type zinc uptake transporter
A, B
291Synechocystis sp. (strain PCC 6803 / Kazusa)Gene Names: zntC
Find proteins for P73085 (Synechocystis sp. (strain PCC 6803 / Kazusa))
Go to UniProtKB:  P73085
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
ZN
Query on ZN

Download SDF File 
Download CCD File 
A, B
ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.9 Å
  • R-Value Free: 0.209 
  • R-Value Work: 0.172 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 64.990α = 90.00
b = 78.300β = 118.32
c = 68.400γ = 90.00
Software Package:
Software NamePurpose
PROTEUM PLUSdata reduction
AMoREphasing
CNSrefinement
PROTEUM PLUSdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2003-11-04
    Type: Initial release
  • Version 1.1: 2008-04-29
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Source and taxonomy, Version format compliance