University of Pittsburgh scientists have developed novel nucleic acid aptamers for selective covalent binding to target proteins allowing for a multitude of functions including protein modification and labeling.
Description
Aptamers are synthetic short DNA or RNA strands capable of folding into a unique 3D structure that selectively recognizes proteins. These novel aptamers include a cleavable electrophile which covalently binds and transfers to nucleophilic residues on a target protein. By directly modifying a targeted protein, this allows for labeling, drug delivery, or degradation to interfere with downstream effects, providing a host or therapeutic and diagnostic uses.
Applications
• Drug delivery
• Labeling proteins of interest
• Specific protein targeting for detection, degradation, or immune response redirection
Advantages
Antibodies are commonly used to selectively target proteins but attract a high cost due to challenges with production consistency and shelf-life. Although aptamers have been explored as potential protein modifiers, challenges around stability in cells, fast off rates (impacting target engagement) and the laborious selection and design process have hindered development.
These novel aptamers overcome these challenges. The cleavable electrophile results in covalent bonding between the aptamer and target protein, eliminating off rates and allowing aptamer use in more applications than currently possible (labeling of proteins, drug delivery, etc.). These new aptamers will provide the specificity, binding affinity and versatility of an antibody without the high production cost. Additionally, a new method has been developed to generate aptamers for any protein to target any user-specified nucleophilic residue.
Invention Readiness
Initial work incorporated an N-acyl sulfonamide cleavable electrophile (known to selectively react with lysine) with a biotin label into a thrombin binding aptamer (TBA) to produce a TBA-electrophile (TBA-1). TBA-1 reacted with thrombin in human serum to selectively biotinylate thrombin at the aptamer-protein binding interface. Binding was found to be selective and fast. Further work produced fluorescently labeled thrombin. Use of an inverted electrophile led to a stable aptamer-thrombin crosslink, inhibiting thrombin functionality. Other work targeting tyrosine-protein kinase-like 7 and the SARS-CoV-2 surface protein highlights the versatility of these aptamers to target, label, or inhibit activity in a wide variety of proteins.
IP Status
https://patents.google.com/patent/US20240255495A1
