Summary information and primary citation
- PDB-id
-
2m58;
DSSR-derived features in text and
JSON formats
- Class
- RNA
- Method
- NMR
- Summary
- Structure of 2'-5' ag1 lariat forming ribozyme in its
inactive state
- Reference
-
Carlomagno T, Amata I, Codutti L, Falb M, Fohrer J,
Masiewicz P, Simon B (2013): "Structural
principles of RNA catalysis in a 2'-5' lariat-forming
ribozyme." J.Am.Chem.Soc.,
135, 4403-4411. doi: 10.1021/ja311868t.
- Abstract
- RNA-catalyzed lariat formation is present in both
eukaryotes and prokaryotes. To date we lack structural
insights into the catalytic mechanism of lariat-forming
ribozymes. Here, we study an artificial 2'-5' AG1
lariat-forming ribozyme that shares the sequence
specificity of lariat formation with the pre-mRNA splicing
reaction. Using NMR, we solve the structure of the inactive
state of the ribozyme in the absence of magnesium. The
reaction center 5'-guanosine appears to be part of a helix
with an exceptionally widened major groove, while the
lariat-forming A48 is looped out at the apex of a
pseudoknot. The model of the active state built by
mutational analysis, molecular modeling, and small-angle
X-ray scattering suggests that A48 is recognized by a
conserved adenosine, juxtaposed to the 5'-guanosine in one
base-pair step distance, while the G1-N7 coordinates a
magnesium ion essential for the activation of the
nucleophile. Our findings offer implications for lariat
formation in RNA enzymes including the mechanism of the
recognition of the branch-site adenosine.
