Why Target Protein Kinases with Aptamers? Protein kinases are a large family of enzymes that regulate almost all cellular processes by phosphorylating target proteins. Their dysregulation is a hallmark of many diseases, especially cancer, making them prime therapeutic targets. Advantages of Aptamers over Traditional Kinase Inhibitors: High Specificity: Can be selected to distinguish between highly conserved kinase family members or even between active/inactive conformations. Modifiable Chemistry: Easy chemical modification for stability (e.g., 2'-F, 2'-O-methyl) and labeling (e.g., fluorophores, biotin). Non-Immunogenic: Unlike antibodies, they are chemically synthesized, reducing batch-to-batch variability. Reversible Inhibition: Typically act as competitive inhibitors, which can be desirable for certain therapeutic strategies. Cell-Permeable Versions: Spiegelmers (L-aptamers) or nanoparticle conjugation can enable intracellular targeting. Core Screening Service Workflow (SELEX) The service revolves around SELEX (Systematic Evolution of Ligands by EXponential Enrichment), specifically optimized for kinases. 1. Project Design & Library Selection: Target Definition: Which kinase? Which conformation (active, inactive, substrate-bound)? Which domain (catalytic, regulatory)? Library Design: Standard DNA/RNA libraries or modified (e.g., 2'-F pyrimidines for nuclease resistance). Library diversity is typically >10^14 unique sequences. 2. Target Preparation: Protein Quality is Critical: The kinase must be highly pure, correctly folded, and functional. Services often use recombinant kinases with tags (GST, His) for immobilization. Immobilization Strategy: Crucial step. Common methods include: Biotin-Streptavidin: Biotinylated…
