3F72

Crystal Structure of the Staphylococcus aureus pI258 CadC Metal Binding Site 2 Mutant


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.31 Å
  • R-Value Free: 0.288 
  • R-Value Work: 0.237 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Role of bound Zn(II) in the CadC Cd(II)/Pb(II)/Zn(II)-responsive repressor.

Kandegedara, A.Thiyagarajan, S.Kondapalli, K.C.Stemmler, T.L.Rosen, B.P.

(2009) J.Biol.Chem. 284: 14958-14965

  • DOI: 10.1074/jbc.M809179200

  • PubMed Abstract: 
  • The Staphylococcus aureus plasmid pI258 cadCA operon encodes a P-type ATPase, CadA, that confers resistance to Cd(II)/Pb(II)/Zn(II). Expression is regulated by CadC, a homodimeric repressor that dissociates from the cad operator/promoter upon binding ...

    The Staphylococcus aureus plasmid pI258 cadCA operon encodes a P-type ATPase, CadA, that confers resistance to Cd(II)/Pb(II)/Zn(II). Expression is regulated by CadC, a homodimeric repressor that dissociates from the cad operator/promoter upon binding of Cd(II), Pb(II), or Zn(II). CadC is a member of the ArsR/SmtB family of metalloregulatory proteins. The crystal structure of CadC shows two types of metal binding sites, termed Site 1 and Site 2, and the homodimer has two of each. Site 1 is the physiological inducer binding site. The two Site 2 metal binding sites are formed at the dimerization interface. Site 2 is not regulatory in CadC but is regulatory in the homologue SmtB. Here the role of each site was investigated by mutagenesis. Both sites bind either Cd(II) or Zn(II). However, Site 1 has higher affinity for Cd(II) over Zn(II), and Site 2 prefers Zn(II) over Cd(II). Site 2 is not required for either derepression or dimerization. The crystal structure of the wild type with bound Zn(II) and of a mutant lacking Site 2 was compared with the SmtB structure with and without bound Zn(II). We propose that an arginine residue allows for Zn(II) regulation in SmtB and, conversely, a glycine results in a lack of regulation by Zn(II) in CadC. We propose that a glycine residue was ancestral whether the repressor binds Zn(II) at a Site 2 like CadC or has no Site 2 like the paralogous ArsR and implies that acquisition of regulatory ability in SmtB was a more recent evolutionary event.


    Organizational Affiliation

    Department of Biochemistry and Molecular Biology, Wayne State University, School of Medicine, Detroit, Michigan 48201, USA.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Cadmium efflux system accessory protein
A, B, C, D, E, F
122Staphylococcus aureusMutation(s): 3 
Gene Names: cadC
Find proteins for P20047 (Staphylococcus aureus)
Go to UniProtKB:  P20047
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
NA
Query on NA

Download SDF File 
Download CCD File 
A, B, F
SODIUM ION
Na
FKNQFGJONOIPTF-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.31 Å
  • R-Value Free: 0.288 
  • R-Value Work: 0.237 
  • Space Group: P 43
Unit Cell:
Length (Å)Angle (°)
a = 89.471α = 90.00
b = 89.471β = 90.00
c = 148.536γ = 90.00
Software Package:
Software NamePurpose
SCALEPACKdata scaling
HKL-2000data collection
HKL-2000data scaling
PDB_EXTRACTdata extraction
PHASERphasing
HKL-2000data reduction
REFMACrefinement
DENZOdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2009-04-07
    Type: Initial release
  • Version 1.1: 2011-07-13
    Type: Version format compliance
  • Version 1.2: 2017-10-25
    Type: Refinement description