1HQ1: Structural and Energetic Analysis of RNA Recognition by a Universally Conserved Protein From the Signal Recognition Particle

The signal recognition particle (SRP) is a ribonucleoprotein complex responsible for targeting proteins to the endoplasmic reticulum in eukarya or to the inner membrane in prokarya. The crystal structure of the universally conserved RNA-protein core of the Escherichia coli SRP, refined here to 1.5 A resolution, revealed minor groove recognition of the 4.5 S RNA component by the M domain of the Ffh protein. Within the RNA, nucleotides comprising two phylogenetically conserved internal loops create a unique surface for protein recognition. To determine the energetic importance of conserved nucleotides for SRP assembly, we measured the affinity of the M domain for a series of RNA mutants. This analysis reveals how conserved nucleotides within the two internal loop motifs establish the architecture of the macromolecular interface and position essential functional groups for direct recognition by the protein.
PDB ID: 1HQ1Download
MMDB ID: 72304
PDB Deposition Date: 2000/12/13
Updated in MMDB: 2011/06
Experimental Method:
x-ray diffraction
Resolution: 1.52  Å
Source Organism:
Escherichia coli
Similar Structures:
Biological Unit for 1HQ1: dimeric; determined by author
Molecular Components in 1HQ1
Label Count Molecule
Protein (1 molecule)
Signal Recognition Particle Protein
Molecule annotation
Nucleotide(1 molecule)
4.5s RNA Domain IV
Molecule annotation
Chemicals (7 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB