4MA9

Wild type Salmonella Alkyl Hydroperoxide Reductase C in its substrate-ready conformation


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.82 Å
  • R-Value Free: 0.240 
  • R-Value Work: 0.204 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

The sensitive balance between the fully folded and locally unfolded conformations of a model peroxiredoxin.

Perkins, A.Nelson, K.J.Williams, J.R.Parsonage, D.Poole, L.B.Karplus, P.A.

(2013) Biochemistry 52: 8708-8721

  • DOI: 10.1021/bi4011573
  • Primary Citation of Related Structures:  
    4MAB, 4MA9

  • PubMed Abstract: 
  • To reduce peroxides, peroxiredoxins (Prxs) require a key "peroxidatic" Cys that, in a substrate-ready fully folded (FF) conformation, is oxidized to sulfenic acid and then, after a local unfolding (LU) of the active site, forms a disulfide bond with a second "resolving" Cys ...

    To reduce peroxides, peroxiredoxins (Prxs) require a key "peroxidatic" Cys that, in a substrate-ready fully folded (FF) conformation, is oxidized to sulfenic acid and then, after a local unfolding (LU) of the active site, forms a disulfide bond with a second "resolving" Cys. For Salmonella typhimurium alkyl hydroperoxide reductase C (StAhpC) and some other Prxs, the FF structure is only known for a peroxidatic Cys→Ser variant, which may not accurately represent the wild-type enzyme. Here, we obtain the structure of authentic reduced wild-type StAhpC by dithiothreitol treatment of disulfide form crystals that fortuitously accommodate both the LU and FF conformations. The unique environment of one molecule in the crystal reveals a thermodynamic linkage between the folding of the active site loop and C-terminal regions, and comparisons with the Ser variant show structural and mobility differences from which we infer that the Cys→Ser mutation stabilizes the FF active site. A structure for the C165A variant (a resolving Cys to Ala mutant) in the same crystal form reveals that this mutation destabilizes the folding of the C-terminal region. These structures prove that subtle modifications to Prx structures can substantially influence enzymatic properties. We also present a simple thermodynamic framework for understanding the various mixtures of FF and LU conformations seen in these structures. On the basis of this framework, we rationalize how physiologically relevant regulatory post-translational modifications may modulate activity, and we propose a nonconventional strategy for designing selective Prx inhibitors.


    Organizational Affiliation

    Department of Biochemistry and Biophysics, Oregon State University , Corvallis, Oregon 97331, United States.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Alkyl hydroperoxide reductase subunit CA, B, C, D, E186Salmonella enterica subsp. enterica serovar TyphimuriumMutation(s): 0 
Gene Names: ahpCahpC STM0608STM0608
EC: 1.11.1.15 (PDB Primary Data), 1.11.1.26 (UniProt)
Find proteins for P0A251 (Salmonella typhimurium (strain LT2 / SGSC1412 / ATCC 700720))
Explore P0A251 
Go to UniProtKB:  P0A251
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.82 Å
  • R-Value Free: 0.240 
  • R-Value Work: 0.204 
  • Space Group: C 2 2 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 126.84α = 90
b = 171.15β = 90
c = 135.32γ = 90
Software Package:
Software NamePurpose
PHASERphasing
BUSTERrefinement
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2013-11-20
    Type: Initial release
  • Version 1.1: 2013-11-27
    Changes: Database references
  • Version 1.2: 2014-02-12
    Changes: Database references