The Ca2+ -Regulated Photoprotein Obelin as a Tool for SELEX Monitoring and DNA Aptamer Affinity Evaluation.

Bioluminescent solid-phase analysis was proposed to monitor the selection process and to determine binding characteristics of the aptamer-target complexes during design and development of the specific aptamers. The assay involves Ca2+ -regulated photoprotein obelin as a simple, sensitive and fast reporter. Applicability and the prospects of the approach were exemplified by identification of DNA aptamers to cardiac troponin I, a highly specific early biomarker for acute myocardial infarction. Two structurally different aptamers specific to various epitopes of troponin I were obtained and then tested in a model bioluminescent assay.