0000000000409105
AUTHOR
Lorenz J. Steinbock
Rupture Force of Single Small Drug Molecule Binding a Split Aptamer
Aptamers are specific oligonucleotides (DNA or RNA) which bind small inorganic or organic molecules, large proteins or cells. In particular, the high affinity of aptamers is expected to lead to a new class of therapeutic reagents. Thus the detection and characterization of binding strength of small molecules is important for drug and medical research. Atomic force spectroscopy (AFS) with a force resolution in the piconewton range is a valuable tool for studying interactions on a single molecular level. The detection of very small target molecules less than 500 Dalton is characterized by only a few hydrogen interactions between the aptamer and the target molecules. Thus tiny rupture forces w…
Measuring single small molecule binding via rupture forces of a split aptamer.
The rupture force of a split (bipartite) aptamer that forms binding pockets for adenosine monophosphate (AMP) was measured by atomic force spectroscopy. Changes in the rupture force were observed in the presence of AMP, while this effect was absent when mutant aptamers or inosine were used. Thus, changes in the rupture force were a direct consequence of specific binding of AMP to the split aptamer. The split aptamer concept allowed the detection of nonlabeled AMP and enabled us to determine the dissociation constant on a single-molecule level.