1ZK7

Crystal Structure of Tn501 MerA


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.60 Å
  • R-Value Free: 0.212 
  • R-Value Work: 0.192 
  • R-Value Observed: 0.192 

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This is version 1.2 of the entry. See complete history


Literature

NmerA, the Metal Binding Domain of Mercuric Ion Reductase, Removes Hg(2+) from Proteins, Delivers It to the Catalytic Core, and Protects Cells under Glutathione-Depleted Conditions

Ledwidge, R.Patel, B.Dong, A.Fiedler, D.Falkowski, M.Zelikova, J.Summers, A.O.Pai, E.F.Miller, S.M.

(2005) Biochemistry 44: 11402-11416

  • DOI: 10.1021/bi050519d
  • Primary Citation of Related Structures:  
    1ZK7, 1ZX9

  • PubMed Abstract: 
  • The ligand binding and catalytic properties of heavy metal ions have led to the evolution of metal ion-specific pathways for control of their intracellular trafficking and/or elimination. Small MW proteins/domains containing a GMTCXXC metal binding motif in a betaalphabetabetaalphabeta fold are common among proteins controlling the mobility of soft metal ions such as Cu(1+), Zn(2+), and Hg(2+), and the functions of several have been established ...

    The ligand binding and catalytic properties of heavy metal ions have led to the evolution of metal ion-specific pathways for control of their intracellular trafficking and/or elimination. Small MW proteins/domains containing a GMTCXXC metal binding motif in a betaalphabetabetaalphabeta fold are common among proteins controlling the mobility of soft metal ions such as Cu(1+), Zn(2+), and Hg(2+), and the functions of several have been established. In bacterial mercuric ion reductases (MerA), which catalyze reduction of Hg(2+) to Hg(0) as a means of detoxification, one or two repeats of sequences with this fold are highly conserved as N-terminal domains (NmerA) of uncertain function. To simplify functional analysis of NmerA, we cloned and expressed the domain and catalytic core of Tn501 MerA as separate proteins. In this paper, we show Tn501 NmerA to be a stable, soluble protein that binds 1 Hg(2+)/domain and delivers it to the catalytic core at kinetically competent rates. Comparison of steady-state data for full-length versus catalytic core MerA using Hg(glutathione)(2) or Hg(thioredoxin) as substrate demonstrates that the NmerA domain does participate in acquisition and delivery of Hg(2+) to the catalytic core during the reduction catalyzed by full-length MerA, particularly when Hg(2+) is bound to a protein. Finally, comparison of growth curves for glutathione-depleted Escherichia coli expressing either catalytic core, full-length, or a combination of core plus NmerA shows an increased protection of cells against Hg(2+) in the media when NmerA is present, providing the first evidence of a functional role for this highly conserved domain.


    Organizational Affiliation

    Department of Pharmaceutical Chemistry, University of California-San Francisco, 600 16th Street, San Francisco, California 94143-2280, USA.



Macromolecules
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Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Mercuric reductaseA467Pseudomonas aeruginosaMutation(s): 0 
Gene Names: merA
EC: 1.16.1.1
UniProt
Find proteins for P00392 (Pseudomonas aeruginosa)
Explore P00392 
Go to UniProtKB:  P00392
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.60 Å
  • R-Value Free: 0.212 
  • R-Value Work: 0.192 
  • R-Value Observed: 0.192 
  • Space Group: P 43 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 86.788α = 90
b = 86.788β = 90
c = 136.823γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
CNSrefinement
CNSphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2005-07-05
    Type: Initial release
  • Version 1.1: 2008-04-30
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Derived calculations, Version format compliance