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5MC STANDS FOR 5-METHYLCYTIDINE. THE STRUCTURE IS FORMED OF FOUR EQUIVALENT 5MCCT STRANDS DESIGNATED A, B, C, D. STRANDS A AND C, CONNECTED BY TWO HEMI-PROTONATED BASE PAIRS (5MC1.5MC1+ AND C2.C2+), FORM A PARALLEL-STRANDED DUPLEX. THE RELATION BETWEEN STRANDS B AND D IS THE SAME AS THAT BETWEEN STRANDS A AND C. THE STRANDS OF EACH DUPLEX ARE RELATED BY A LONGITUDINAL TWO-FOLD SYMMETRY AXIS. THE DUPLEXES HAVE THE SAME LONGITUDINAL AXIS, AND THEY ARE ANTI-PARALLEL. THEIR HEMI-PROTONATED C.C+ BASE PAIRS ARE INTERCALATED FACE-TO-FACE. THE DUPLEXES CAN BE TRANSFORMED INTO ONE ANOTHER BY A 180 DEGREE ROTATION AROUND A TWO-FOLD AXIS PERPENDICULAR TO THE LONGITUDINAL AXIS, AND CONSEQUENTLY AROUND A THIRD AXIS PERPENDICULAR TO THE FIRST TWO. THE H3 IMINO PROTONS OF THE HEMI-PROTONATED 5MC1.5MC1+ PAIRS WERE NOT INCORPORATED IN THE COMPUTATIONS. THOSE OF THE C2.C2+ PAIRS WERE ARBITRARILY LOCATED ON THE C2 RESIDUES OF STRANDS A AND B, RESPECTIVELY. |
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