Molecular Recognition of Nucleotide Pairs by a Cyclo-Bis-Intercaland-Type Receptor Molecule: A Spectrophotometric and Electrospray Mass Spectrometry Study
✍ Scribed by Olivier Baudoin; Florence Gonnet; Marie-Paule Teulade-Fichou; Jean-Pierre Vigneron; Jean-Claude Tabet; Jean-Marie Lehn
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 198 KB
- Volume
- 5
- Category
- Article
- ISSN
- 0947-6539
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✦ Synopsis
The water-soluble cyclo-bisintercaland-type receptor molecules 3 a ± c, positively charged macrocyclic polyamines containing two large crescent-shaped quinacridine subunits, bind anionic aromatic substrates, such as nucleotides, by a combination of pstacking and electrostatic noncovalent interactions. Absorption and fluorimetric experiments in aqueous solution show that 3 a ± c form 1:2 (host/guest) noncovalent complexes with nucleoside monophosphates and 1:1 complexes with nucleoside di-and triphosphates. Higher affinities are found for guanosine derivatives than for other nucleo-bases. This unusual binding of a nucleoside monophosphate pair involves pstacking/hydrophobic effects between the nucleobases and the quinacridine subunits of hosts 3 a ± c and possible hydrogen bonding between the two nucleobases within the complex. The results are compared with those obtained with acyclic monomer molecules 4 a ± b and with analogous cyclo-bis-intercalands 1 and 2 bearing smaller aromatic subunits. An electrospray ionization mass spectrometry (ESI-MS) analysis of the noncovalent associations formed between 3 a and nucleoside monophosphates is presented. This technique based on the determination of molecular weight allows the observation of the major 1:2 complexes present in solution with a good preservation of the noncovalent associations during the ionization process. Competition experiments show that the binding selectivity observed for the guanosine derivatives in aqueous solution is preserved in the gas phase.