Affinity analysis between trypsin and aptamers using surface plasmon resonance competition experiments on steady state
A surface plasmon resonance competition experiment on steady state was developed to determine the binding dissociation constants between protein and its DNA aptamers. the affinities of a large set of trypsin aptamers selected by magnetic beads-systematic evolution of ligands by exponential enrichment (MB-SELEX) and capillary electrophoresis (CE- SELEX) are obtained only on one single chip. A large number of chips and much time are saved compared the typical SPR experiment. Additionally, this approach does not require prior knowledge of parameters such as on or off rates, using a nonlinear fitting with a known dissociation constant and the protein concentration as the inputs. the knowledge of the specificity of protein-aptamer interaction are also obtained by the surface plasmon resonance competition experiment.