2GED

Signal Recognition Particle Receptor Beta-Subunit in nucleotide-free dimerized form


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.183 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Homodimerization of the G protein SR{beta} in the nucleotide-free state involves proline cis/trans isomerization in the switch II region.

Schwartz, T.U.Schmidt, D.Brohawn, S.G.Blobel, G.

(2006) Proc.Natl.Acad.Sci.USA 103: 6823-6828

  • DOI: 10.1073/pnas.0602083103

  • PubMed Abstract: 
  • Protein translocation across and insertion into membranes is essential to all life forms. Signal peptide-bearing nascent polypeptide chains emerging from the ribosome are first sampled by the signal-recognition particle (SRP), then targeted to the me ...

    Protein translocation across and insertion into membranes is essential to all life forms. Signal peptide-bearing nascent polypeptide chains emerging from the ribosome are first sampled by the signal-recognition particle (SRP), then targeted to the membrane via the SRP receptor (SR), and, finally, transferred to the protein-conducting channel. In eukaryotes, this process is tightly controlled by the concerted action of three G proteins, the 54-kD subunit of SRP and the alpha- and beta-subunits of SR. We have determined the 2.2-A crystal structure of the nucleotide-free SRbeta domain. Unexpectedly, the structure is a homodimer with a highly intertwined interface made up of residues from the switch regions of the G domain. The remodeling of the switch regions does not resemble any of the known G protein switch mechanisms. Biochemical analysis confirms homodimerization in vitro, which is incompatible with SRalpha binding. The switch mechanism involves cis/trans isomerization of a strictly conserved proline, potentially implying a new layer of regulation of cotranslational transport.


    Related Citations: 
    • Circular permutation as a tool to reduce surface entropy triggers crystallization of the signal recognition particle receptor beta subunit.
      Schwartz, T.U.,Walczak, R.,Blobel, G.
      (2004) Protein Sci. 13: 2814


    Organizational Affiliation

    Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA. tus@mit.edu




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Signal recognition particle receptor beta subunit
A, B
193Saccharomyces cerevisiae (strain ATCC 204508 / S288c)Gene Names: SRP102
Find proteins for P36057 (Saccharomyces cerevisiae (strain ATCC 204508 / S288c))
Go to UniProtKB:  P36057
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
SO4
Query on SO4

Download SDF File 
Download CCD File 
A, B
SULFATE ION
O4 S
QAOWNCQODCNURD-UHFFFAOYSA-L
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.2 Å
  • R-Value Free: 0.239 
  • R-Value Work: 0.183 
  • Space Group: P 61
Unit Cell:
Length (Å)Angle (°)
a = 74.996α = 90.00
b = 74.996β = 90.00
c = 158.475γ = 120.00
Software Package:
Software NamePurpose
DENZOdata reduction
REFMACrefinement
BEASTphasing
SCALEPACKdata scaling

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2006-04-18
    Type: Initial release
  • Version 1.1: 2008-05-01
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance
  • Version 1.3: 2017-08-02
    Type: Source and taxonomy