Biological Assembly 1  

 3D View: Structure | Electron Density

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

Biological assembly 1 assigned by authors.

Macromolecule Content

• Total Structure Weight: 28.68 kDa 
• Atom Count: 2161 
• Residue Count: 260 
• Unique protein chains: 1

2OV1

Crystal structure of apo form of ZnuA with flexible loop deletion

• DOI: 10.2210/pdb2OV1/pdb

• Classification: TRANSPORT PROTEIN
• Organism(s): Synechocystis sp. PCC 6803 substr. Kazusa
• Expression System: Escherichia coli BL21(DE3)
• Mutation(s): No 


• Deposited: 2007-02-12 Released: 2007-07-10 
• Deposition Author(s): Smith, T.J., Wei, B.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.50 Å
• R-Value Free: 0.248 
• R-Value Work: 0.217 
• R-Value Observed: 0.217 

Literature

Possible regulatory role for the histidine-rich loop in the zinc transport protein, ZnuA.

Wei, B., Randich, A.M., Bhattacharyya-Pakrasi, M., Pakrasi, H.B., Smith, T.J.

(2007) Biochemistry 46: 8734-8743

• PubMed: 17616151 
• DOI: 10.1021/bi700763w
• Primary Citation of Related Structures:  
  2OV3, 2OV1


• PubMed Abstract: 
  

A number of bacterial metal transporters belong to the ABC transporter family. To better understand the structural determinants of metal selectivity of one such transporter, we previously determined the structure of the periplasmic domain of a zinc transporter, ZnuA, from Synechocystis 6803 and found that ZnuA binds zinc via three histidines. Unique to these ABC zinc transporters, ZnuA has a highly charged and mobile loop that protrudes from the protein in the vicinity of the metal binding site that we had suggested might facilitate zinc acquisition. To further examine the function of this loop, the structure and zinc binding properties of two ZnuA variants were determined. When the loop is entirely deleted, zinc still binds to the three histidines. However, unlike what was suggested from the structure of a similar solute binding protein, TroA, release of zinc occurs concomitantly with large conformational changes in two of the three chelating histidines. These structural results combined with isothermal titration calorimetry data demonstrate that there are at least two classes of zinc binding sites: the high-affinity site in the cleft between the two domains and at least one additional site on the flexible loop. This loop has approximately 100-fold weaker affinity for zinc than the high-affinity zinc binding site, and its deletion does not affect the high-affinity site. From these results, we suggest that this region might be a sensor for high periplasmic levels of zinc.

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Organizational Affiliation: 

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

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
Periplasmic binding protein component of an ABC type zinc uptake transporter	A	260	Synechocystis sp. PCC 6803 substr. Kazusa	Mutation(s): 0  Gene Names: zntC
Find proteins for P73085 (Synechocystis sp. (strain PCC 6803 / Kazusa)) Explore P73085  Go to UniProtKB:  P73085

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.50 Å
• R-Value Free: 0.248 
• R-Value Work: 0.217 
• R-Value Observed: 0.217 
• Space Group: C 2 2 2₁

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 62.578	α = 90
b = 76.503	β = 90
c = 127.151	γ = 90

Software Package:

Software Name	Purpose
MOLREP	phasing
CNS	refinement
PDB_EXTRACT	data extraction
PROTEUM PLUS	data collection
SAINT	data reduction
PROTEUM PLUS	data scaling

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2007-02-12 
• Released Date: 2007-07-10 
Deposition Author(s): Smith, T.J., Wei, B.

Revision History 

• Version 1.0: 2007-07-10
  Type: Initial release
  
• Version 1.1: 2007-11-14
  Changes: Version format compliance
• Version 1.2: 2011-07-13
  Changes: Version format compliance
• Version 1.3: 2017-06-21
  Changes: Database references, Source and taxonomy