Detection for folding of the thrombin binding aptamer using label-free electrochemical methods.
The folding of aptamer immobilized on an Au electrode was successfully detected using label-free electrochemical methods. A thrombin binding DNA aptamer was used as a model system in the presence of various monovalent cations. Impedance spectra showed that the extent to which monovalent cations assist in folding of aptamer is ordered as K(+) > NH(4)(+) > Na(+) > Cs(+). Our XPS analysis also showed that K(+) and NH(4)(+) caused a conformational change of the aptamer in which it forms a stable complex with these monovalent ions. Impedance results for the interaction between aptamer and thrombin indicated that thrombin interacts more with folded aptamer than with unfolded aptamer. The EQCM technique provided a quantitative analysis of these results. In particular, the present impedance results showed that thrombin participates a folding of aptamer to some extent, and XPS analysis confirmed that thrombin stabilizes and induces the folding of aptamer.
Cho
Minseon
M
Department of Chemistry, Pohang University of Science and Technology, Pohang, Korea.
Kim
Yeonwha
Y
Han
Se-Young
SY
Min
Kyungin
K
Rahman
Md Aminur
MA
Shim
Yoon-Bo
YB
Ban
Changill
C
D052157:Aptamers, Nucleotide / Q000737:chemistry* / Q000378:metabolism*; D015374:Biosensing Techniques; D004563:Electrochemistry / Q000379:methods*; D004566:Electrodes; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D013917:Thrombin / Q000737:chemistry / Q000378:metabolism*
D052157:Aptamers, Nucleotide; C081676:thrombin aptamer; D013917:Thrombin