期刊
BIOCHIMICA ET BIOPHYSICA ACTA-GENERAL SUBJECTS
卷 1830, 期 10, 页码 4935-4942出版社
ELSEVIER SCIENCE BV
DOI: 10.1016/j.bbagen.2013.06.019
关键词
G-Quadruplex; Acidic pH; Conformational interconversion; Nanoswitch; pH-driven; Thiazole orange (TO)
资金
- NSFC [21172272, 91213302, 21102021]
- International S&T Cooperation 85 Program of China [2010DFA34630]
- Hong Kong olytechnic University
- Special Equipment Grant of the University Grants [SEG_PolyU01]
Background: G-Quadruplex is a highly polymorphic structure, and its behavior in acidic condition has not been well studied. Methods: Circular dichroism (CD) spectra were used to study the conformational change of G-quadruplex. The thermal stabilities of the G-quadruplex were measured with CD melting. Interconversion kinetics profiles were investigated by using CD kinetics. The fluorescence of the inserted 2-Aminopurine (Ap) was monitored during pH change and acrylamide quenching, indicating the status of the loop. Proton NMR was adopted to help illustrate the change of the conformation. Results: G-Quadruplex of specific loop was found to be able to transform upon pH variation. The transformation was resulted from the loop rearrangement. After screening of a library of diverse G-quadruplex, a sequence exhibiting the best transformation property was found. A pH-driven nanoswitch with three gears was obtained based on this transition cycle. Conclusions: Certain G-quadruplex was found to go through conformational change at low pH. Loop was the decisive factor controlling the interconversion upon pH variation. G-Quadruplex with TT central loop could be converted in a much milder condition than the one with TTA loop. It can be used to design pH-driven nanodevices such as a nanoswitch. General significance: These results provide more insights into G-quadruplex polymorphism, and also contribute to the design of DNA-based nanomachines and logic gates. (c) 2013 Elsevier B.V. All rights reserved.
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