A Molecular Chaperone for G4-Quartet Hydrogels.

Thioflavin T (ThT) functions as a molecular chaperone for gelation of water by guanosine and lithium borate. Substoichiometric ThT (1 mol % relative to hydrogelator) results in faster hydrogelation as monitored by 1H NMR and visual comparison. Vial-inversion tests and rheology show that ThT increases the stiffness of the Li+ guanosine-borate (GB) hydrogel. In addition, the dye promotes relatively rapid and complete repair of a Li+ GB hydrogel destroyed by shearing. We used rheology to show that other planar aromatics, some cationic and one neutral dye (methylene violet), also stiffened the Li+ GB hydrogel. Data from powder X-ray diffraction, UV, and circular dichroism spectroscopy and ThT fluorescence indicate that G4 quartets are formed by the Li+ GB system. We observed a species in solution by 1H NMR that was intermediate in size between monomeric gelator and NMR-invisible hydrogel. The concentration of this intermediate decreased much faster when ThT was present in solution, again showing that the dye ...