Premium
A Water Soluble Pd 2 L 4 Cage for Selective Binding of Neu5Ac
Author(s) -
Schaapkens Xander,
Sluis Roy N.,
Bobylev Eduard O.,
Reek Joost N. H.,
Mooibroek Tiddo J.
Publication year - 2021
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202102176
Subject(s) - chemistry , hydrogen bond , monosaccharide , selectivity , molecule , sialic acid , solvent , combinatorial chemistry , molecular recognition , nuclear magnetic resonance spectroscopy , salt bridge , stereochemistry , organic chemistry , biochemistry , mutant , gene , catalysis
The sialic acid N ‐acetylneuraminic acid (Neu5Ac) and its derivatives are involved in many biological processes including cell‐cell recognition and infection by influenza. Molecules that can recognize Neu5Ac might thus be exploited to intervene in or monitor such events. A key obstacle in this development is the sparse availability of easily prepared molecules that bind to this carbohydrate in its natural solvent; water. Here, we report that the carbohydrate binding pocket of an organic soluble [Pd 2 L 4 ] 4+ cage could be equipped with guanidinium‐terminating dendrons to give the water soluble [Pd 2 L 4 ][NO 3 ] 16 cage 7 . It was shown by means of NMR spectroscopy that 7 binds selectively to anionic monosaccharides and strongest to Neu5Ac with K a =24 M −1 . The cage had low to no affinity for the thirteen neutral saccharides studied. Aided by molecular modeling, the selectivity for anionic carbohydrates such as Neu5Ac could be rationalized by the presence of charge assisted hydrogen bonds and/or the presence of a salt bridge with a guanidinium solubilizing arm of 7 . Establishing that a simple coordination cage such as 7 can already selectively bind to Neu5Ac in water paves the way to improve the stability, affinity and/or selectivity properties of M 2 L 4 cages for carbohydrates and other small molecules.