Crystal structure of the Sgt2 TPR domain from Aspergillus fumigatus

Experimental Data Snapshot

  • Resolution: 1.72 Å
  • R-Value Free: 0.208 
  • R-Value Work: 0.169 
  • R-Value Observed: 0.173 

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A structural model of the Sgt2 protein and its interactions with chaperones and the Get4/Get5 complex.

Chartron, J.W.Gonzalez, G.M.Clemons, W.M.

(2011) J Biol Chem 286: 34325-34334

  • DOI: https://doi.org/10.1074/jbc.M111.277798
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The insertion of tail-anchored transmembrane (TA) proteins into the appropriate membrane is a post-translational event that requires stabilization of the transmembrane domain and targeting to the proper destination. Sgt2 is a heat-shock protein cognate (HSC) co-chaperone that preferentially binds endoplasmic reticulum-destined TA proteins and directs them to the GET pathway via Get4 and Get5. Here, we present the crystal structure from a fungal Sgt2 homolog of the tetratrico-repeat (TPR) domain and part of the linker that connects to the C-terminal domain. The linker extends into the two-carboxylate clamp of the TPR domain from a symmetry-related molecule mimicking the binding to HSCs. Based on this structure, we provide biochemical evidence that the Sgt2 TPR domain has the ability to directly bind multiple HSC family members. The structure allows us to propose features involved in this lower specificity relative to other TPR containing co-chaperones. We further show that a dimer of Sgt2 binds a single Get5 and use small angle x-ray scattering to characterize the domain arrangement of Sgt2 in solution. These results allow us to present a structural model of the Sgt2-Get4/Get5-HSC complex.

  • Organizational Affiliation

    Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Hsc70 cochaperone (SGT)164Aspergillus fumigatus Af293Mutation(s): 0 
Gene Names: AFUA_1G09830
Find proteins for Q4WTC0 (Aspergillus fumigatus (strain ATCC MYA-4609 / CBS 101355 / FGSC A1100 / Af293))
Explore Q4WTC0 
Go to UniProtKB:  Q4WTC0
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ4WTC0
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.72 Å
  • R-Value Free: 0.208 
  • R-Value Work: 0.169 
  • R-Value Observed: 0.173 
  • Space Group: F 2 2 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 59.61α = 90
b = 86.77β = 90
c = 116.54γ = 90
Software Package:
Software NamePurpose
SCALAdata scaling
PDB_EXTRACTdata extraction
Blu-Icedata collection
MOSFLMdata reduction

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2011-08-10
    Type: Initial release
  • Version 1.1: 2012-08-29
    Changes: Database references
  • Version 1.2: 2023-09-13
    Changes: Data collection, Database references, Refinement description