Structure of Hg-NmerA, Hg(II) complex of the N-terminal domain of Tn501 Mercuric Reductase

Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the lowest energy 

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NmerA of Tn501 mercuric ion reductase: structural modulation of the pKa values of the metal binding cysteine thiols.

Ledwidge, R.Hong, B.Dotsch, V.Miller, S.M.

(2010) Biochemistry 49: 8988-8998

  • DOI: https://doi.org/10.1021/bi100537f
  • Primary Citation of Related Structures:  
    2KT2, 2KT3

  • PubMed Abstract: 

    To avoid nonspecific and/or undesirable binding and reactivity of metal ions with cellular components, organisms have evolved metal-specific systems for trafficking proteins. Although systems differ, those handling soft metal ions such as Hg(2+), Cu(+), Zn(2+), etc., all utilize heavy metal-associated (HMA) proteins and domains of ~70 amino acids with a conserved GMXCXXC motif in a βαββαβ structural fold. While the conserved cysteines define a common metal binding site in these proteins, other structural features must be utilized to create metal ion, protein partner, and contextual specificities. This paper presents initial structure-function studies of the N-terminal HMA domain (NmerA) of Tn501 mercuric ion reductase (MerA) aimed at identifying structural features critical to its role in facilitating efficient transfer of Hg(2+) to the MerA catalytic core for reductive detoxification. First, NMR solution structures of reduced and Hg(2+)-bound forms of NmerA are presented that allow definition and comparison of the structure of the metal binding loop in the two states. Structural differences between the two forms are compared with differences observed in three HMA domains with different metal ion and functional contexts. Second, analyses of the UV absorbance properties of wild-type, Cys11Ala, and Cys14Ala forms of NmerA are presented that provide assignments of the pK(a) values for the two cysteine thiols of the metal binding motif. Third, results from ¹³C NMR studies with wild-type and Y62F NmerA labeled with [β-¹³C]cysteine are presented that define a role for Tyr62 in modulating the pK(a) values of the cysteine thiols.

  • Organizational Affiliation

    Department of Pharmaceutical Chemistry, University of California-San Francisco, 600 16th Street, San Francisco, CA 94158-2517, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Mercuric reductase69Pseudomonas aeruginosaMutation(s): 0 
Gene Names: merA
Find proteins for P00392 (Pseudomonas aeruginosa)
Explore P00392 
Go to UniProtKB:  P00392
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP00392
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on HG

Download Ideal Coordinates CCD File 
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the lowest energy 

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2010-09-22
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2020-02-26
    Changes: Data collection, Database references, Other
  • Version 1.3: 2023-06-14
    Changes: Database references, Derived calculations, Other