Crystal Structure of Human Saposin C

Experimental Data Snapshot

  • Resolution: 2.40 Å
  • R-Value Free: 0.283 
  • R-Value Work: 0.211 
  • R-Value Observed: 0.221 

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This is version 1.3 of the entry. See complete history


Crystal structures of saposins A and C.

Ahn, V.E.Leyko, P.Alattia, J.R.Chen, L.Prive, G.G.

(2006) Protein Sci 15: 1849-1857

  • DOI: https://doi.org/10.1110/ps.062256606
  • Primary Citation of Related Structures:  
    2DOB, 2GTG

  • PubMed Abstract: 

    Saposins A and C are sphingolipid activator proteins required for the lysosomal breakdown of galactosylceramide and glucosylceramide, respectively. The saposins interact with lipids, leading to an enhanced accessibility of the lipid headgroups to their cognate hydrolases. We have determined the crystal structures of human saposins A and C to 2.0 Angstroms and 2.4 Angstroms, respectively, and both reveal the compact, monomeric saposin fold. We confirmed that these two proteins were monomeric in solution at pH 7.0 by analytical centrifugation. However, at pH 4.8, in the presence of the detergent C(8)E(5), saposin A assembled into dimers, while saposin C formed trimers. Saposin B was dimeric under all conditions tested. The self-association of the saposins is likely to be relevant to how these small proteins interact with lipids, membranes, and hydrolase enzymes.

  • Organizational Affiliation

    Department of Medical Biophysics, University of Toronto, Canada.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Proactivator polypeptide83Homo sapiensMutation(s): 0 
Gene Names: PSAP
UniProt & NIH Common Fund Data Resources
Find proteins for P07602 (Homo sapiens)
Explore P07602 
Go to UniProtKB:  P07602
GTEx:  ENSG00000197746 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP07602
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.40 Å
  • R-Value Free: 0.283 
  • R-Value Work: 0.211 
  • R-Value Observed: 0.221 
  • Space Group: P 63
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 53.204α = 90
b = 53.204β = 90
c = 52.46γ = 120
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2006-07-25
    Type: Initial release
  • Version 1.1: 2008-05-01
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Advisory, Version format compliance
  • Version 1.3: 2023-08-30
    Changes: Data collection, Database references, Refinement description