Using gold aggregation to probe the inhibition and destruction of the G-quadruplex structure by TT-dimerization

Thrombin binding G-quadruplex oligonucleotide containing two TT-dimer fragments and a gold attachment (ODN G1-G) was designed and synthesized with the aim of understanding the TT-dimer effect in G-quadruplex formation. Our results showed that TT-dimer mutation induced by UV light inhibits the formation of and even destroys the G-quadruplex structure, as confirmed by UV, CD and melting temperature measurements. The structural change resulting from TT-dimer formation with DNA was additionally probed and was found to be accompanied by significant gold aggregation that was observed in the form of a signal change from red to blue.