4XHM

Archaeoglobus fulgidus thioredoxin 3 M60H


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.95 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.191 
  • R-Value Observed: 0.194 

wwPDB Validation   3D Report Full Report


This is version 1.2 of the entry. See complete history


Literature

Rheostat Re-Wired: Alternative Hypotheses for the Control of Thioredoxin Reduction Potentials.

Bewley, K.D.Dey, M.Bjork, R.E.Mitra, S.Chobot, S.E.Drennan, C.L.Elliott, S.J.

(null) PLoS One 10: e0122466-e0122466

  • DOI: 10.1371/journal.pone.0122466
  • Primary Citation of Related Structures:  
    4XHM

  • PubMed Abstract: 
  • Thioredoxins are small soluble proteins that contain a redox-active disulfide (CXXC). These disulfides are tuned to oxidizing or reducing potentials depending on the function of the thioredoxin within the cell. The mechanism by which the potential is tuned has been controversial, with two main hypotheses: first, that redox potential (Em) is specifically governed by a molecular 'rheostat'-the XX amino acids, which influence the Cys pKa values, and thereby, Em; and second, the overall thermodynamics of protein folding stability regulates the potential ...

    Thioredoxins are small soluble proteins that contain a redox-active disulfide (CXXC). These disulfides are tuned to oxidizing or reducing potentials depending on the function of the thioredoxin within the cell. The mechanism by which the potential is tuned has been controversial, with two main hypotheses: first, that redox potential (Em) is specifically governed by a molecular 'rheostat'-the XX amino acids, which influence the Cys pKa values, and thereby, Em; and second, the overall thermodynamics of protein folding stability regulates the potential. Here, we use protein film voltammetry (PFV) to measure the pH dependence of the redox potentials of a series of wild-type and mutant archaeal Trxs, PFV and glutathionine-equilibrium to corroborate the measured potentials, the fluorescence probe BADAN to measure pKa values, guanidinium-based denaturation to measure protein unfolding, and X-ray crystallography to provide a structural basis for our functional analyses. We find that when these archaeal thioredoxins are probed directly using PFV, both the high and low potential thioredoxins display consistent 2H+:2e- coupling over a physiological pH range, in conflict with the conventional 'rheostat' model. Instead, folding measurements reveals an excellent correlation to reduction potentials, supporting the second hypothesis and revealing the molecular mechanism of reduction potential control in the ubiquitous Trx family.


    Organizational Affiliation

    Department of Chemistry, Boston University, Boston, Massachusetts, United States of America.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
Thioredoxin (Trx-3)A, B137Archaeoglobus fulgidus DSM 4304Mutation(s): 1 
Gene Names: AF_1284
Find proteins for O28984 (Archaeoglobus fulgidus (strain ATCC 49558 / VC-16 / DSM 4304 / JCM 9628 / NBRC 100126))
Explore O28984 
Go to UniProtKB:  O28984
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.95 Å
  • R-Value Free: 0.250 
  • R-Value Work: 0.191 
  • R-Value Observed: 0.194 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 49.564α = 90
b = 56.905β = 90
c = 100.076γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
PHASERphasing
Cootmodel building
PHENIXrefinement
CNSrefinement
REFMACrefinement
PDB_EXTRACTdata extraction

Structure Validation

View Full Validation Report



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Howard Hughes Medical Institute (HHMI)United States--
National Science Foundation (NSF, United States)United StatesMCB 1122977

Revision History  (Full details and data files)

  • Version 1.0: 2015-04-29
    Type: Initial release
  • Version 1.1: 2017-09-06
    Changes: Advisory, Author supporting evidence, Derived calculations, Source and taxonomy
  • Version 1.2: 2019-11-20
    Changes: Author supporting evidence