1X8W: Structure Of The Tetrahymena Ribozyme: Base Triple Sandwich And Metal Ion At The Active Site

The Tetrahymena intron is an RNA catalyst, or ribozyme. As part of its self-splicing reaction, this ribozyme catalyzes phosphoryl transfer between guanosine and a substrate RNA strand. Here we report the refined crystal structure of an active Tetrahymena ribozyme in the absence of its RNA substrate at 3.8 A resolution. The 3'-terminal guanosine (omegaG), which serves as the attacking group for RNA cleavage, forms a coplanar base triple with the G264-C311 base pair, and this base triple is sandwiched by three other base triples. In addition, a metal ion is present in the active site, contacting or positioned close to the ribose of the omegaG and five phosphates. All of these phosphates have been shown to be important for catalysis. Therefore, we provide a picture of how the ribozyme active site positions both a catalytic metal ion and the nucleophilic guanosine for catalysis prior to binding its RNA substrate.
PDB ID: 1X8WDownload
MMDB ID: 51967
PDB Deposition Date: 2004/8/18
Updated in MMDB: 2007/10
Experimental Method:
x-ray diffraction
Resolution: 3.8  Å
Biological Unit for 1X8W: monomeric; determined by author
Molecular Components in 1X8W
Label Count Molecule
Nucleotide(1 molecule)
Tetrahymena Ribozyme RNA
Molecule annotation
Chemicals (6 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB