High efficiency acetylcholinesterase immobilization on DNA aptamer modified surfaces

Area of Science:

• Biochemistry
• Molecular Biology
• Biotechnology

Background:

• Acetylcholinesterase (AChE) is a crucial enzyme in neurotransmission.
• Aptamers are short DNA or RNA sequences that bind to specific targets.
• Developing specific aptamers for AChE can lead to novel diagnostic and therapeutic tools.

Purpose of the Study:

• To select and characterize DNA aptamers that bind to electric eel acetylcholinesterase (AChE).
• To evaluate the binding affinity and stability of the selected aptamers under varying ionic conditions.
• To assess the impact of aptamer immobilization on AChE activity.

Main Methods:

• In vitro selection (SELEX) was used to identify DNA aptamers against electric eel AChE.
• Surface Plasmon Resonance (SPR) was employed to determine the binding affinity (Kd) of the aptamer.
• Enzyme kinetics assays were performed to measure AChE catalytic activity after immobilization.

Main Results:

• One aptamer, R15/19, exhibited high affinity for AChE with a dissociation constant (Kd) of 157±42 pM.
• Aptamer binding was stable at low ionic strength but decreased significantly at high ionic strength.
• Immobilization of AChE via the aptamer resulted in a four-fold increase in catalytic activity compared to direct adsorption.

Conclusions:

• DNA aptamers can be effectively selected for specific binding to electric eel AChE.
• The R15/19 aptamer demonstrates high affinity and functional properties suitable for enzyme immobilization.
• Aptamer-mediated immobilization enhances AChE catalytic activity, suggesting potential applications in biosensors and enzyme-based technologies.