Artificial receptors: molecular imprints discern closely related toxins

• Published in: Materials Science & Engineering C 1999-12, Vol.7 (2), p.77-81
• Main Authors: Iqbal, Shahzi S, Lulka, Mark F, Chambers, James P, Thompson, Roy G, Valdes, James J
• Format: Article
• Language: English
• Subjects: Artificial receptors; Biological and medical sciences; Biosensors; Biotechnology; Closely related toxins; Fundamental and applied biological sciences. Psychology; Methods. Procedures. Technologies; Molecular imprints; Various methods and equipments
• ISSN: 0928-4931; 1873-0191
• DOI: 10.1016/S0928-4931(99)00090-9

We describe silane molecular imprints which can discriminate closely related toxins, supporting the potential usefulness of molecular imprints as artificial receptors, i.e., sensing elements, for detection of biological toxins. Molecular imprints to N-acetylated μ-Conotoxin GIIIB (NacGIIIB) were prepared and binding assays carried out using [14C]-NacGIIIB. In accordance with a Type I Langmuir adsorption isotherm, saturation of NacGIIIB imprint binding sites occurred at approximately 6.25 μM and Scatchard analysis revealed a relatively high binding affinity (Kd=0.37 nM). Binding assays carried out in the presence of a 10-fold molar excess of unlabeled ligand (NacGIIIB) indicated a significant decrease in bound [14C]-NacGIIIB, i.e., >90%. In contrast, incubation of [14C]-NacGIIIB with GIIIA or GIIIB as well as a variety of other Conotoxins demonstrated no significant competition. However, NacGIIIB's closest congener, i.e., NacGIIIA, competed, but required a higher concentration (K0.5≅12.5 μM) to achieve 50% reduction in binding of [14C]-NacGIIIB than that observed for NacGIIIB (K0.5≅6.25 μM). These results suggest that simple silane imprints can discern subtle differences in tertiary structure of closely related small proteins.