1f27

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Revision as of 10:33, 8 November 2007

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spinqualitylabelsall models 1f27, resolution 1.30Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

CRYSTAL STRUCTURE OF A BIOTIN-BINDING RNA PSEUDOKNOT

Overview

A pseudoknot-containing aptamer isolated from a pool of random sequence, molecules has been shown previously to represent an optimal RNA solution, to the problem of binding biotin. The affinity of this RNA molecule is, nonetheless orders of magnitude weaker than that of its highly evolved, protein analogs, avidin and streptavidin. To understand the structural, basis for biotin binding and to compare directly strategies for ligand, recognition available to proteins and RNA molecules, we have determined, the 1.3 A crystal structure of the aptamer complexed with its ligand., Biotin is bound at the interface between the pseudoknot's stacked helices, in a pocket defined almost entirely by base-paired nucleotides. In, comparison to the protein avidin, the aptamer packs more tightly around, the biotin headgroup and makes fewer contacts with its fatty acid tail., Whereas biotin is deeply buried within the hydrophobic core in the avidin, complex, the aptamer relies on a combination of hydrated magnesium ions, and immobilized water molecules to surround its ligand. In addition to, demonstrating fundamentally different approaches to molecular recognition, by proteins and RNA, the structure provides general insight into the, mechanisms by which RNA function is mediated by divalent metals.

About this Structure

1F27 is a Protein complex structure of sequences from [1] with MG and BTN as ligands. Full crystallographic information is available from OCA.

Reference

The 1.3 A crystal structure of a biotin-binding pseudoknot and the basis for RNA molecular recognition., Nix J, Sussman D, Wilson C, J Mol Biol. 2000 Mar 10;296(5):1235-44. PMID:10698630

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