Interaction of three-way DNA junctions with steroids
Related Experiment Video
Updated: Oct 17, 2026

Human Neuroendocrine Tumor Cell Lines as a Three-Dimensional Model for the Study of Human Neuroendocrine Tumor Therapy
Published on: August 14, 2012
1Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan.
Abstract:
DNA aptamers that bind to cholic acid were previously isolated by an in vitro selection method. Secondary structural prediction and deletion-mutant experiments suggested that the cholic-acid binding regions of 19 sequenced clones could form three-way-junction structures. In this article, the secondary structures of the sequenced clones and the structural requirements for binding to cholic acid were evaluated. A course of mutational-analysis and chemical-modification experiments provided strong support for the predicted secondary structure and also indicated that the binding site is located at the branching point of the three-way junction. Sequence analysis revealed that the sequences of the three base pairs flanking the junction of the three stems are highly conserved among selected clones. The evaluation of the relative binding of several bile acids and structurally related steroids with the aptamer was also carried out. The results revealed a broad range of selectivity and preference for hydrophobic steroids rather than for cholic acid upon binding, indicating that the binding is driven by a hydrophobic interaction. The experimental results reported here allowed us to propose a structural model of a binding site formed by three Watson-Crick base pairs.
More Related Videos
11:07Biochemical Reconstitution of Steroid Receptor•Hsp90 Protein Complexes and Reactivation of Ligand Binding
Published on: September 21, 2011
10:51Reverse Yeast Two-hybrid System to Identify Mammalian Nuclear Receptor Residues that Interact with Ligands and/or Antagonists
Published on: November 15, 2013
Related Concept Videos
Intracellular Hormone Receptors
Types of Receptors: Internal Receptors
Similar to membrane-bound receptors, the binding of a ligand to the intracellular receptor of causes a conformational change in the...
Signal Transduction: Overview
Typically, signal transduction involves three...
Drug-Receptor Bonds
In...
Internal Receptors
Transducer Mechanism: Nuclear Receptors
About 48 different soluble family members of nuclear receptors are identified that can be divided into two main classes: