Thymine quantum chemical calculation

A similar topic was examined by Ida (Ida and Wu 2008). In this study, molecular dynamics was employed exploring G-quadruplex stabilized by Na and Rb cations, which were found to be tightly bound to a quadruplex structure. Moreover, in d(G(4)T(4)G(4) sequences the Na ions are found to be located in the diagonal T-4 loop region of the G-quadruplex, which is formed by two strands of d(G4T4G4) sequence. The authors proposed that the loop Na ion is located above the terminal G-quartet, coordinating to four guanine 06 atoms from the terminal G-quartet and one 02 atom from a loop thymine base and one water molecule. The Na coordination was also supported by quantum chemical calculations on Na chemical shifts. 

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