3GOT: Guanine Riboswitch C74u Mutant Bound To 2-Fluoroadenine

Purine riboswitches discriminate between guanine and adenine by at least 10,000-fold based on the identity of a single pyrimidine (Y74) that forms a Watson-Crick base pair with the ligand. To understand how this high degree of specificity for closely related compounds is achieved through simple pairing, we investigated their interaction with purine analogs with varying functional groups at the 2- and 6-positions that have the potential to alter interactions with Y74. Using a combination of crystallographic and calorimetric approaches, we find that binding these purines is often facilitated by either small structural changes in the RNA or tautomeric changes in the ligand. This work also reveals that, along with base pairing, conformational restriction of Y74 significantly contributes to nucleobase selectivity. These results reveal that compounds that exploit the inherent local flexibility within riboswitch binding pockets can alter their ligand specificity.
PDB ID: 3GOTDownload
MMDB ID: 73887
PDB Deposition Date: 2009/3/20
Updated in MMDB: 2011/10
Experimental Method:
x-ray diffraction
Resolution: 1.95  Å
Biological Unit for 3GOT: monomeric; determined by author
Molecular Components in 3GOT
Label Count Molecule
Nucleotide(1 molecule)
Guanine Riboswitch
Molecule annotation
Chemicals (13 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB