Naslov
Effect of structure levels on surface-enhanced Raman scattering of human telomeric G-quadruplexes in diluted and crowded media

Autori
Papi, Francesco ; Kenđel, Adriana ; Ratkaj, Marina ; Piantanida, Ivo ; Gratteri, Paola ; Bazzicalupi, Carla ; Miljanić, Snežana

Izvornik
Analytical and bioanalytical chemistry (1618-2642) 411 (2019); 5197-5207

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
structure level ; SERS ; CD ; G-quadruplex ; human telomere ; crowding

Sažetak
Human telomeric G-quadruplexes are emerging targets in anticancer drug discovery since they are able to efficiently inhibit telomerase, an enzyme which is greatly involved in telomere instability and immortalization process in malignant cells. G-quadruplex (G4) DNA is highly polymorphic and can adopt different topologies upon addition of electrolytes, additives and ligands. Study of G-quadruplex forms under various conditions, however, might be quite challenging. In this work surface-enhanced Raman scattering (SERS) spectroscopy has been applied to study G-quadruplexes formed by human telomeric sequences, d[A3G3(TTAGGG)3A2] (Tel26) and d[(TTAGGG)4T2] (wtTel26), under dilute and crowding conditions. The SERS spectra distinctive of hybrid-1 and hybrid-2 G-quadruplexes of Tel26 and wtTel26, respectively, were observed for the sequences folded in presence of K+ ions (110 mM) in a buffered solution, representing the diluted medium. Polyethylene glycol (5, 10, 15, 20 and 40% v/v PEG) was used to create molecular-crowded environment, resulting in formation of the parallel G-quadruplexes of both studied human telomeric sequences. Despite extensive overlap by the crowding agent bands, the SERS spectral features indicative of the parallel G4 forms were recognized. The obtained results implied that SERS of G-quadruplexes reflected not only the primary structure of the studied human telomeric sequence, including its nucleobase composition and sequence, but also its secondary structure in sense of Hoogsteen hydrogen bonds responsible for the guanine tetrads formation, and finally its tertiary structure, defining a three-dimensional DNA shape, positioned close to the enhancing metallic surface.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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