1B4Q

Solution structure of human thioltransferase complex with glutathione


Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 95 
  • Conformers Submitted: 21 

wwPDB Validation   3D Report Full Report


This is version 1.4 of the entry. See complete history


Literature

Reactivity of the human thioltransferase (glutaredoxin) C7S, C25S, C78S, C82S mutant and NMR solution structure of its glutathionyl mixed disulfide intermediate reflect catalytic specificity.

Yang, Y.Jao, S.Nanduri, S.Starke, D.W.Mieyal, J.J.Qin, J.

(1998) Biochemistry 37: 17145-17156

  • DOI: https://doi.org/10.1021/bi9806504
  • Primary Citation of Related Structures:  
    1B4Q

  • PubMed Abstract: 

    Human thioltransferase (TTase) is a 12 kDa thiol-disulfide oxidoreductase that appears to play a critical role in maintaining the redox environment of the cell. TTase acts as a potent and specific reducing agent for protein-S-S-glutathione mixed disulfides (protein-SSG) likely formed during oxidative stress or as redox intermediates in signal transduction pathways. Accordingly, the catalytic cycle of thioltransferase itself involves a covalent glutathionyl enzyme disulfide intermediate (TTase-C22-SSG). To understand the molecular basis of TTase specificity for the glutathione moiety, we engineered a quadruple Cys to Ser mutant of human TTase (C7S, C25S, C78S, and C82S) which retains only the active site cysteine residue (C22), and we solved its high-resolution NMR solution structure in the mixed disulfide intermediate with glutathione (QM-TTase-SSG). This mutant which cannot form a C22-S-S-C25 intramolecular disulfide displays the same catalytic efficiency (Vmax/KM) and specificity for glutathionyl mixed disulfide substrates as wild-type TTase, indicating that the Cys-25-SH moiety is not required for catalysis or glutathionyl specificity. The structure of human thioltransferase is characterized by a thioredoxin-like fold which comprises a four-stranded central beta-sheet flanked on each side by alpha-helices. The disulfide-adducted glutathione in the TTase-SSG complex has an extended conformation and is localized in a cleft near the protein surface encompassing the residues from helices-alpha2,alpha3, the active site loop, and the loop connecting helix-alpha3 and strand-beta3. Numerous van der Waals and electrostatic interactions between the protein and the glutathione moiety are identified as contributing to stabilization of the complex and confering the substrate specificity. Comparison of the human thioltransferase with other thiol-disulfide oxidoreductases reveals structural and functional differences.


  • Organizational Affiliation

    Structural Biology Program, Department of Molecular Cardiology, Lerner Research Institute, The Cleveland Clinic Foundation, Ohio 44195, USA.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
PROTEIN (HUMAN THIOLTRANSFERASE)105Homo sapiensMutation(s): 4 
UniProt & NIH Common Fund Data Resources
Find proteins for P35754 (Homo sapiens)
Explore P35754 
Go to UniProtKB:  P35754
PHAROS:  P35754
GTEx:  ENSG00000173221 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP35754
Sequence Annotations
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  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
GSH
Query on GSH

Download Ideal Coordinates CCD File 
B [auth A]GLUTATHIONE
C10 H17 N3 O6 S
RWSXRVCMGQZWBV-WDSKDSINSA-N
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 95 
  • Conformers Submitted: 21 

Structure Validation

View Full Validation Report



Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 1999-12-23
    Type: Initial release
  • Version 1.1: 2008-04-27
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2021-11-03
    Changes: Database references, Derived calculations
  • Version 1.4: 2023-12-27
    Changes: Data collection