Designed, functionalized helix-loop-helix motifs that bind human carbonic anhydrase II: a new class of synthetic receptor molecules
2004 (English)In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 126, no 14, 4464-4465 p.Article in journal (Refereed) Published
Polypeptides designed to fold into helix−loop−helix motifs and to dimerize to form four-helix bundles were functionalized by the introduction of a sulfonamide derivative known to bind human carbonic anhydrase II (HCAII) and one or both of the dansyl- and methoxycoumarin fluorescent probes. The 42-residue sequence DC that carries all three substituents in solvent-exposed positions was found to bind HCAII with a dissociation constant of 5 nM in aqueous solution at pH 7. At 2 μM concentration, DC was mainly dimeric in aqueous solution but bound HCAII as a monomer. Upon addition of a large excess of a helix−loop−helix motif without a high-affinity ligand, KE2-Q, a ternary complex was formed between HCAII, DC, and KE2-Q. Hydrophobic interactions between DC and HCAII and coordination of the sulfonamide group to the zinc ion of HCAII contributed cooperatively to binding in a demonstration of the usefulness of folded polypeptide−small organic molecule chimera as novel protein receptors. The DC homodimer was found to be a very sensitive biosensor component due to intermolecular quenching of its fluorescence that was inhibited upon binding to HCAII.
Place, publisher, year, edition, pages
2004. Vol. 126, no 14, 4464-4465 p.
Engineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-45770DOI: 10.1021/ja038799cOAI: oai:DiVA.org:liu-45770DiVA: diva2:266666