7kd1 | pdb_00007kd1

Apo structure of the THF riboswitch aptamer domain

spinqualitylabelsall models 7kd1, resolution 1.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 7kd1 is a 1 chain structure. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: MG, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed Effective gene regulation by the tetrahydrofolate riboswitch depends not only on ligand affinity but also on the kinetics of ligand association, which involves two cooperative binding sites. We have determined a 1.9-A resolution crystal structure of the ligand-free THF riboswitch aptamer. The pseudoknot binding site 'unwinds' in the absence of ligand, whereby the adjacent helical domains (P1, P2, and P3) become disjointed, resulting in rotation and misalignment of the gene-regulatory P1 helix with respect to P3. In contrast, the second binding site at the three-way junction, which is the first to fold, is structurally conserved between apo and holo forms. This suggests a kinetic role for this site, in which binding of the first ligand molecule to the stably folded three-way junction promotes formation of the regulatory pseudoknot site and subsequent binding of the second molecule. As such, these findings provide a molecular basis for both conformational switching and kinetic control. Tying the knot in the tetrahydrofolate (THF) riboswitch: A molecular basis for gene regulation.,Wilt HM, Yu P, Tan K, Wang YX, Stagno JR J Struct Biol. 2021 Feb 9;213(1):107703. doi: 10.1016/j.jsb.2021.107703. PMID:33571639 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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