NMR structure of the cadmium metal-sensor CMTR from Mycobacterium tuberculosis

Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 300 
  • Conformers Submitted: 30 
  • Selection Criteria: target function 

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NMR Structural Analysis of Cadmium Sensing by Winged Helix Repressor CmtR.

Banci, L.Bertini, I.Cantini, F.Ciofi-Baffoni, S.Cavet, J.S.Dennison, C.Graham, A.I.Harvie, D.R.Robinson, N.J.

(2007) J Biol Chem 282: 30181-30188

  • DOI: https://doi.org/10.1074/jbc.M701119200
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    CmtR from Mycobacterium tuberculosis is a winged helical DNA-binding repressor of the ArsR-SmtB metal-sensing family that senses cadmium and lead. Cadmium-CmtR is a dimer with the metal bound to Cys-102 from the C-terminal region of one subunit and two Cys associated with helix alphaR from the other subunit, forming a symmetrical pair of cadmium-binding sites. This is a significant novelty in the ArsR-SmtB family. The structure of the dimer could be solved at 312 K. The apoprotein at the same temperature is still a dimer, but it experiences a large conformational exchange at the dimer interface and within each monomer. This is monitored by an overall decrease of the number of nuclear Overhauser effects and by an increase of H(2)O-D(2)O exchange rates, especially at the dimeric interface, in the apo form with respect to the cadmium-bound state. The C-terminal tail region is completely unstructured in both apo and cadmium forms but becomes less mobile in the cadmium-bound protein due to the recruitment of Cys-102 as a metal-ligand. DNA binds to the apo dimer with a ratio 1:3 at millimolar concentration. Addition of cadmium to the apo-CmtR-DNA complex causes DNA detachment, restoring the NMR spectrum of free cadmium-CmtR. Cadmium binding across the dimer interface impairs DNA association by excluding the apo-conformers suited to bind DNA.

  • Organizational Affiliation

    Department of Chemistry and Centro Risonanze Magnetiche, University of Florence, Via Luigi Sacconi 6, Florence 50019, Italy.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Transcriptional regulator Rv1994c/MT2050
A, B
118Mycobacterium tuberculosis H37RvMutation(s): 0 
Gene Names: Rv1994cMT2050MTCY39.25
Find proteins for P9WMI9 (Mycobacterium tuberculosis (strain ATCC 25618 / H37Rv))
Explore P9WMI9 
Go to UniProtKB:  P9WMI9
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP9WMI9
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on CD

Download Ideal Coordinates CCD File 
C [auth A],
D [auth B]
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 300 
  • Conformers Submitted: 30 
  • Selection Criteria: target function 

Structure Validation

View Full Validation Report

Entry History 

Revision History  (Full details and data files)

  • Version 1.0: 2007-07-31
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Source and taxonomy, Version format compliance
  • Version 1.2: 2023-12-20
    Changes: Data collection, Database references, Derived calculations, Other