20
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Selection of DNA aptamers using atomic force microscopy

      research-article

      Read this article at

      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Atomic force microscopy (AFM) can detect the adhesion or affinity force between a sample surface and cantilever, dynamically. This feature is useful as a method for the selection of aptamers that bind to their targets with very high affinity. Therefore, we propose the Systematic Evolution of Ligands by an EXponential enrichment (SELEX) method using AFM to obtain aptamers that have a strong affinity for target molecules. In this study, thrombin was chosen as the target molecule, and an ‘AFM-SELEX’ cycle was performed. As a result, selected cycles were completed with only three rounds, and many of the obtained aptamers had a higher affinity to thrombin than the conventional thrombin aptamer. Moreover, one type of obtained aptamer had a high affinity to thrombin as well as the anti-thrombin antibody. AFM-SELEX is, therefore, considered to be an available method for the selection of DNA aptamers that have a high affinity for their target molecules.

          Related collections

          Most cited references28

          • Record: found
          • Abstract: found
          • Article: not found

          Systematic evolution of ligands by exponential enrichment: RNA ligands to bacteriophage T4 DNA polymerase.

          L Gold, C Tuerk (1990)
          High-affinity nucleic acid ligands for a protein were isolated by a procedure that depends on alternate cycles of ligand selection from pools of variant sequences and amplification of the bound species. Multiple rounds exponentially enrich the population for the highest affinity species that can be clonally isolated and characterized. In particular one eight-base region of an RNA that interacts with the T4 DNA polymerase was chosen and randomized. Two different sequences were selected by this procedure from the calculated pool of 65,536 species. One is the wild-type sequence found in the bacteriophage mRNA; one is varied from wild type at four positions. The binding constants of these two RNA's to T4 DNA polymerase are equivalent. These protocols with minimal modification can yield high-affinity ligands for any protein that binds nucleic acids as part of its function; high-affinity ligands could conceivably be developed for any target molecule.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            A DNA aptamer that binds adenosine and ATP.

            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.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Diversity of oligonucleotide functions.

              SELEX is a technology for the identification of high affinity oligonucleotide ligands. Large libraries of random sequence single-stranded oligonucleotides, whether RNA or DNA, can be thought of conformationally not as short strings but rather as sequence dependent folded structures with high degrees of molecular rigidity in solution. This conformational complexity means that such a library is a source of high affinity ligands for a surprising variety of molecular targets, including nucleic acid binding proteins such as polymerases and transcription factors, non-nucleic acid binding proteins such as cytokins and growth factors, as well as small organic molecules such as ATP and theophylline. The range of applications of this technology for new discovery extends from basic research reagents to the identification of novel diagnostic and therapeutic reagents. Examples of these applications are described along with a discussion of underlying principles and future developments expected to further the utility of SELEX.
                Bookmark

                Author and article information

                Journal
                Nucleic Acids Res
                Nucleic Acids Res
                nar
                nar
                Nucleic Acids Research
                Oxford University Press
                0305-1048
                1362-4962
                March 2010
                2 December 2009
                2 December 2009
                : 38
                : 4
                : e21
                Affiliations
                1Department of Chemical Science and Engineering Faculty of Engineering, Graduate School of Engineering, Kobe University, Rokkoudai-chou 1-1, Nada, Kobe 657-8501 and 2Division of Material Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Japan
                Author notes
                *To whom correspondence should be addressed. Tel/Fax:+81 78 803 6193; Email: ochiaki@ 123456port.kobe-u.ac.jp
                Article
                gkp1101
                10.1093/nar/gkp1101
                2831320
                19955232
                5e2bf8f4-e05e-4a27-8fc9-62107ffb3cd1
                © The Author(s) 2009. Published by Oxford University Press.

                This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License ( http://creativecommons.org/licenses/by-nc/2.5), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

                History
                : 10 August 2009
                : 23 October 2009
                : 9 November 2009
                Categories
                Methods Online

                Genetics
                Genetics

                Comments

                Comment on this article