1Q96: Crystal Structure Of A Mutant Of The SarcinRICIN DOMAIN From Rat 28s Rrna

Bulged-G motifs are ubiquitous internal RNA loops that provide specific recognition sites for proteins and RNAs. To establish the common and distinctive features of the motif we determined the structures of three variants and compared them with related structures. The variants are 27-nt mimics of the sarcin/ricin loop (SRL) from Escherichia coli 23S ribosomal RNA that is an essential part of the binding site for elongation factors (EFs). The wild-type SRL has now been determined at 1.04 A resolution, supplementing data obtained before at 1.11 A and allowing the first calculation of coordinate error for an RNA motif. The other two structures, having a viable (C2658U*G2663A) or a lethal mutation (C2658G*G2663C), were determined at 1.75 and 2.25 A resolution, respectively. Comparisons reveal that bulged-G motifs have a common hydration and geometry, with flexible junctions at flanking structural elements. Six conserved nucleotides preserve the fold of the motif; the remaining seven to nine vary in sequence and alter contacts in both grooves. Differences between accessible functional groups of the lethal mutation and those of the viable mutation and wild-type SRL may account for the impaired elongation factor binding to ribosomes with the C2658G*G2663C mutation and may underlie the lethal phenotype.
PDB ID: 1Q96Download
MMDB ID: 50929
PDB Deposition Date: 2003/8/22
Updated in MMDB: 2007/10
Experimental Method:
x-ray diffraction
Resolution: 1.75  Å
Source Organism:
Biological Unit for 1Q96: monomeric; determined by author
Molecular Components in 1Q96
Label Count Molecule
Nucleotide(1 molecule)
Sarcinricin 28S rRNA
Molecule annotation
Chemicals (2 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB