The crystal structure of the signal recognition particle in complex with its receptor

Science. 2011 Feb 18;331(6019):881-6. doi: 10.1126/science.1196473.

Abstract

Cotranslational targeting of membrane and secretory proteins is mediated by the universally conserved signal recognition particle (SRP). Together with its receptor (SR), SRP mediates the guanine triphosphate (GTP)-dependent delivery of translating ribosomes bearing signal sequences to translocons on the target membrane. Here, we present the crystal structure of the SRP:SR complex at 3.9 angstrom resolution and biochemical data revealing that the activated SRP:SR guanine triphosphatase (GTPase) complex binds the distal end of the SRP hairpin RNA where GTP hydrolysis is stimulated. Combined with previous findings, these results suggest that the SRP:SR GTPase complex initially assembles at the tetraloop end of the SRP RNA and then relocalizes to the opposite end of the RNA. This rearrangement provides a mechanism for coupling GTP hydrolysis to the handover of cargo to the translocon.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / chemistry*
  • Bacterial Proteins / metabolism
  • Base Sequence
  • Binding Sites
  • Crystallization
  • Crystallography, X-Ray
  • Enzyme Activation
  • Escherichia coli / chemistry
  • Escherichia coli / metabolism
  • Escherichia coli Proteins / chemistry*
  • Escherichia coli Proteins / metabolism
  • GTP Phosphohydrolases / chemistry
  • GTP Phosphohydrolases / metabolism
  • Guanosine Triphosphate / analogs & derivatives
  • Guanosine Triphosphate / chemistry
  • Guanosine Triphosphate / metabolism
  • Hydrogen Bonding
  • Hydrophobic and Hydrophilic Interactions
  • Models, Biological
  • Models, Molecular
  • Nucleic Acid Conformation
  • Protein Conformation
  • Protein Multimerization
  • Protein Structure, Tertiary
  • Protein Transport
  • RNA, Bacterial / chemistry*
  • RNA, Bacterial / metabolism
  • Receptors, Cytoplasmic and Nuclear / chemistry*
  • Receptors, Cytoplasmic and Nuclear / metabolism
  • Ribosomal Proteins / chemistry
  • Ribosomal Proteins / metabolism
  • Ribosomes / metabolism
  • Signal Recognition Particle / chemistry*
  • Signal Recognition Particle / metabolism

Substances

  • 4.5S RNA
  • Bacterial Proteins
  • Escherichia coli Proteins
  • Ffh protein, E coli
  • FtsY protein, Bacteria
  • RNA, Bacterial
  • Receptors, Cytoplasmic and Nuclear
  • Ribosomal Proteins
  • Signal Recognition Particle
  • ribosomal protein L23, E coli
  • ribosomal protein L29
  • 5'-guanylylmethylenebisphosphonate
  • Guanosine Triphosphate
  • GTP Phosphohydrolases

Associated data

  • PDB/2XXA