A DNA aptamer that binds adenosine and ATP
| Autor: | Jack W. Szostak, David E. Huizenga |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
Base Sequence
Stereochemistry Aptamer Adenine Mutagenesis Molecular Sequence Data DNA Ligand (biochemistry) Biochemistry Adenosine chemistry.chemical_compound Adenosine Triphosphate chemistry medicine Nucleic Acid Conformation A-DNA Cloning Molecular Adenosine triphosphate medicine.drug Binding domain |
| Zdroj: | Biochemistry. 34(2) |
| ISSN: | 0006-2960 |
| Popis: | We have used in vitro selection to isolate adenosine/ATP-binding DNA sequences from a pool of approximately 2 x 10(14) different random-sequence single-stranded DNA molecules. One of these aptamers has been characterized and binds adenosine in solution with a dissociation constant of 6 +/- 3 microM. Experiments with ATP analogs indicate that functional groups on both the base and the sugar of ATP are involved in the ligand/aptamer interaction. The binding domain of this aptamer was localized to a 42 base sequence by deletion analysis. A pool of mutagenized versions of this sequence was then synthesized and screened for functional adenosine binding sequences; comparison of the selected variants revealed two highly conserved guanosine-rich regions, two invariant adenosine residues, and two regions of predominantly Watson--Crick covariation. This data led us to propose a model of the ATP-binding DNA structure which is based on a stable framework composed of two stacked G-quartets. The two highly conserved adenosine residues may stack between the top G-quartet and the two short stems, forming a pocket in which the adenosine or ATP ligand binds. Site-directed mutagenesis, base analog substitution studies, and the design of highly divergent but functional sequences provide support for this model. |
| Databáze: | OpenAIRE |
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