U4/U6 snRNP-specific cyclophilin SnuCyp-20

Experimental Data Snapshot

  • Resolution: 2.00 Å
  • R-Value Free: 0.224 
  • R-Value Work: 0.170 
  • R-Value Observed: 0.170 

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This is version 1.4 of the entry. See complete history


Crystal Structure of the Human U4/U6 Small Nuclear Ribonucleoproteinparticle-Specificsnucyp-20, a Nuclear Cyclophilin

Reidt, U.Reuter, K.Achsel, T.Ingelfinger, D.Luehrmann, R.Ficner, R.

(2000) J Biol Chem 275: 7439

  • DOI: https://doi.org/10.1074/jbc.275.11.7439
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The cyclophilin SnuCyp-20 is a specific component of the human U4/U6 small nuclear ribonucleoprotein particle involved in the nuclear splicing of pre-mRNA. It stably associates with the U4/U6-60kD and -90kD proteins, the human orthologues of the Saccharomyces cerevisiae Prp4 and Prp3 splicing factors. We have determined the crystal structure of SnuCyp-20 at 2.0-A resolution by molecular replacement. The structure of SnuCyp-20 closely resembles that of human cyclophilin A (hCypA). In particular, the catalytic centers of SnuCyp-20 and hCypA superimpose perfectly, which is reflected by the observed peptidyl-prolyl-cis/trans-isomerase activity of SnuCyp-20. The surface properties of both proteins, however, differ significantly. Apart from seven additional amino-terminal residues, the insertion of five amino acids in the loop alpha1-beta3 and of one amino acid in the loop alpha2-beta8 changes the conformations of both loops. The enlarged loop alpha1-beta3 is involved in the formation of a wide cleft with predominantly hydrophobic character. We propose that this enlarged loop is required for the interaction with the U4/U6-60kD protein.

  • Organizational Affiliation

    Institut für Molekularbiologie und Tumorforschung, Universität Marburg, 35037 Marburg, Germany.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
SNUCYP-20177Homo sapiensMutation(s): 0 
Gene Names: SNUCYP-20
UniProt & NIH Common Fund Data Resources
Find proteins for O43447 (Homo sapiens)
Explore O43447 
Go to UniProtKB:  O43447
PHAROS:  O43447
GTEx:  ENSG00000171960 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupO43447
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.00 Å
  • R-Value Free: 0.224 
  • R-Value Work: 0.170 
  • R-Value Observed: 0.170 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 47.3α = 90
b = 59.9β = 90
c = 60.7γ = 90
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: 2000-04-10
    Type: Initial release
  • Version 1.1: 2011-05-08
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Version format compliance
  • Version 1.3: 2017-07-05
    Changes: Data collection
  • Version 1.4: 2023-12-13
    Changes: Data collection, Database references, Other, Refinement description