3SD3

The structure of the tetrahydrofolate riboswitch containing a U25C mutation

Summary for 3SD3

• Entry DOI: 10.2210/pdb3sd3/pdb
• Related: 3SD1
• Descriptor: Tetrahydrofolate riboswitch, IRIDIUM HEXAMMINE ION, N-[4-({[(6S)-2-amino-5-formyl-4-oxo-3,4,5,6,7,8-hexahydropteridin-6-yl]methyl}amino)benzoyl]-L-glutamic acid, ... (4 entities in total)
• Functional Keywords: tetrahydrofolate rna riboswitch, rna
• Total number of polymer chains: 1
• Total formula weight: 30793.60

Authors

Reyes, F.E.,Trausch, J.J.,Ceres, P.,Batey, R.T. (deposition date: 2011-06-08, release date: 2011-09-21, Last modification date: 2024-02-28)

Primary citation

Trausch, J.J.,Ceres, P.,Reyes, F.E.,Batey, R.T.
The structure of a tetrahydrofolate-sensing riboswitch reveals two ligand binding sites in a single aptamer.
Structure, 19:1413-1423, 2011

PubMed Abstract: Transport and biosynthesis of folate and its derivatives are frequently controlled by the tetrahydrofolate (THF) riboswitch in Firmicutes. We have solved the crystal structure of the THF riboswitch aptamer in complex with folinic acid, a THF analog. Uniquely, this structure reveals two molecules of folinic acid binding to a single structured domain. These two sites interact with ligand in a similar fashion, primarily through recognition of the reduced pterin moiety. 7-deazaguanine, a soluble analog of guanine, binds the riboswitch with nearly the same affinity as its natural effector. However, 7-deazaguanine effects transcriptional termination to a substantially lesser degree than folinic acid, suggesting that the cellular guanine pool does not act upon the THF riboswitch. Under physiological conditions the ligands display strong cooperative binding, with one of the two sites playing a greater role in eliciting the regulatory response, which suggests that the second site may play another functional role.

PubMed: 21906956
DOI: 10.1016/j.str.2011.06.019

Experimental method

X-RAY DIFFRACTION (1.95 Å)