4P3E: Structure Of The Human Srp S Domain

The signal recognition particle (SRP) is central to membrane protein targeting; SRP RNA is essential for SRP assembly, elongation arrest, and activation of SRP guanosine triphosphatases. In eukaryotes, SRP function relies on the SRP68-SRP72 heterodimer. We present the crystal structures of the RNA-binding domain of SRP68 (SRP68-RBD) alone and in complex with SRP RNA and SRP19. SRP68-RBD is a tetratricopeptide-like module that binds to a RNA three-way junction, bends the RNA, and inserts an alpha-helical arginine-rich motif (ARM) into the major groove. The ARM opens the conserved 5f RNA loop, which in ribosome-bound SRP establishes a contact to ribosomal RNA. Our data provide the structural basis for eukaryote-specific, SRP68-driven RNA remodeling required for protein translocation.
PDB ID: 4P3EDownload
MMDB ID: 119262
PDB Deposition Date: 2014/2/25
Updated in MMDB: 2017/10
Experimental Method:
x-ray diffraction
Resolution: 3.5  Å
Source Organism:
Similar Structures:
Biological Unit for 4P3E: trimeric; determined by author and by software (PISA)
Molecular Components in 4P3E
Label Count Molecule
Proteins (2 molecules)
Signal Recognition Particle 19 KDA Protein(Gene symbol: SRP19)
Molecule annotation
Signal Recognition Particle Subunit Srp68(Gene symbol: SRP68)
Molecule annotation
Nucleotide(1 molecule)
SRP RNA (124-mer)
Molecule annotation
Chemicals (4 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB