Geometrical effect of 3D-memory cavity on the imprinting efficiency of transition-state analogue-built artificial hydrolases
Highlighting biomimetic recognition and shape-selective binding, highly crosslinked transition-state analogue-imprinted artificial hydrolases are synthesized from amino acid monomers. Two different transition-state analogues—TSAs—are used for the preparation of the enzyme mimic polymer catalysts. The catalytic hydrolysis of amino acid p-nitroanilides is found to be dependent on the geometry of the TSA imprints on the polymer matrix. The imprinted TSA facilitates tetrahedral complementarity to the transition-state intermediate of hydrolysis. The geometry of the 3D-memory cavity fabricated by the print molecule along with the catalytic entities is accountable for the higher catalytic competence of the imprinted enzyme mimics over the non-imprinted control polymers. The super crosslinked macroporous polymer matrix, in which the catalytic functions are suitably oriented in a ‘3D pocket’ for selective binding of the substrate through H-bonding, is accountable for the high imprinting efficiency of the imprinted polymer catalysts. The imprinted mimics are found to be exhibiting cross-selectivity in their catalytic properties. Even though the mimics could not compete with native enzyme, they exhibit higher thermal stability, increased shelf-life and superior reusability.
KeywordsTransition-state analogue Artificial hydrolases Substrate recognition 3D-memory cavity Cross-selectivity and shape-selective hydrolysis
The authors gratefully acknowledge the support from Council of Scientific and Industrial Research (CSIR) India for awarding junior and senior research fellowships to Divya Mathew. We are also thankful to Institute for Integrated Programmes and Research in Basic Sciences (IIRBS)-Mahatma Gandhi University, Kottayam, India, for providing facilities for spectral analysis and School of Biosciences, Mahatma Gandhi University, Kottayam, India, for providing facilities for incubation studies.
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