Human steroid receptor RNA activator protein carboxy-terminal domain

Experimental Data Snapshot

  • Resolution: 2.81 Å
  • R-Value Free: 0.278 
  • R-Value Work: 0.245 
  • R-Value Observed: 0.247 

wwPDB Validation   3D Report Full Report

This is version 1.2 of the entry. See complete history


Structure and function of steroid receptor RNA activator protein, the proposed partner of SRA noncoding RNA.

McKay, D.B.Xi, L.Barthel, K.K.Cech, T.R.

(2014) J Mol Biol 426: 1766-1785

  • DOI: https://doi.org/10.1016/j.jmb.2014.01.006
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    In a widely accepted model, the steroid receptor RNA activator protein (SRA protein; SRAP) modulates the transcriptional regulatory activity of SRA RNA by binding a specific stem-loop of SRA. We first confirmed that SRAP is present in the nucleus as well as the cytoplasm of MCF-7 breast cancer cells, where it is expressed at the level of about 10(5) molecules per cell. However, our SRAP-RNA binding experiments, both in vitro with recombinant protein and in cultured cells with plasmid-expressed protein and RNA, did not reveal a specific interaction between SRAP and SRA. We determined the crystal structure of the carboxy-terminal domain of human SRAP and found that it does not have the postulated RRM (RNA recognition motif). The structure is a five-helix bundle that is distinct from known RNA-binding motifs and instead is similar to the carboxy-terminal domain of the yeast spliceosome protein PRP18, which stabilizes specific protein-protein interactions within a multisubunit mRNA splicing complex. SRA binding experiments with this domain gave negative results. Transcriptional regulation by SRA/SRAP was examined with siRNA knockdown. Effects on both specific estrogen-responsive genes and genes identified by RNA-seq as candidates for regulation were examined in MCF-7 cells. Only a small effect (~20% change) on one gene resulting from depletion of SRA/SRAP could be confirmed. We conclude that the current model for SRAP function must be reevaluated; we suggest that SRAP may function in a different context to stabilize specific intermolecular interactions in the nucleus.

  • Organizational Affiliation

    BioFrontiers Institute, University of Colorado, Boulder, CO 80309, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Steroid receptor RNA activator 1
A, B
111Homo sapiensMutation(s): 0 
Gene Names: PP7684sraSRA1
UniProt & NIH Common Fund Data Resources
Find proteins for Q9HD15 (Homo sapiens)
Explore Q9HD15 
Go to UniProtKB:  Q9HD15
GTEx:  ENSG00000213523 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9HD15
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 2.81 Å
  • R-Value Free: 0.278 
  • R-Value Work: 0.245 
  • R-Value Observed: 0.247 
  • Space Group: P 43 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 85.901α = 90
b = 85.901β = 90
c = 100.408γ = 90
Software Package:
Software NamePurpose
ADSCdata collection
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2014-02-05
    Type: Initial release
  • Version 1.1: 2014-10-08
    Changes: Database references
  • Version 1.2: 2023-09-20
    Changes: Data collection, Database references, Refinement description