Allosteric Recognition of Homomeric and Heteromeric Pairs of Monosaccharides by a Foldamer Capsule
作者:Pedro Mateus、Nagula Chandramouli、Cameron D. Mackereth、Brice Kauffmann、Yann Ferrand、Ivan Huc
DOI:10.1002/anie.201914929
日期:2020.3.27
was evidenced by circular dichroism (CD), NMRspectroscopy, and X-raycrystallography. The cavity of the host was predicted to be large enough to accommodate simultaneously two xylose molecules and to form a 1:2 complex (one container, two saccharides). Solution and solid-state data revealed the selective recognition of the α-4 C1 -d-xylopyranose tautomer, which is bound at two identical sites in the
An aromatic oligoamide sequence was designed and synthesized to fold in a single helix having a large cavity and to behave as a host for a dumbbell-shaped guest derived from tartaric acid. NMR, molecular modeling, and circular dichroism (CD) evidence demonstrated the rapid formation of this 1:1 host-guest complex and induction of the helix handedness of the host by the guest. This complex was found to be a long-lived kinetic supramolecular byproduct, as it slowly transformed into a 2:2 host-guest complex with two guest molecules bound at the extremities of a double helix formed by the host, as shown by NMR and CD spectroscopy and a solid-state structure. The guest also induced the handedness of the double helical host, but with an opposite bias. The chiroptical properties of the system were thus found to revert with time as the 1:1 complex formed first, followed by the 2:2 complex.