Natural evolution has created biopolymers on the basis of amino acids and nucleotides showing high chemical selectivity and catalytic power. Molecular recognition by antibodies and catalytic conversion of the substrate molecules by enzymes take place in so called paratopes or catalytic centres of the macromolecule which comprise typically 10-15 amino acids. The concerted interaction between the reaction partners result in affinities down to nanomolar concentrations for the antigen binding and approaches one million turnovers per second in enzyme-catalyzed reactions.
Nucleic acids bind complimentary single stranded nucleic acids by base pairing (hybridisation) with nanomolar affinities but also interact highly specific with proteins, e.g. transcription factors, and low-molecular weight molecules and even with ions.
Biomimetic binders and catalysts have been generated using “evolution in the test tube” of non-natural nucleotides or total chemical synthesis of (molecularly imprinted) polymers in order to substitute the biological pendants in bioanalysis.