June 07, 2010
Image of Isocytosine 3D Image of Isocytosine

Isocytosine (2-aminouracil) is a non-natural nucleobase and an isomer of one of the four main bases in DNA and RNA. It pairs in a “reversed Watson–Crick” manner with natural guanine or in a normal manner with non-natural isoguanine. In aqueous solution, it exists as two tautomers, the one shown and the other with a proton on the ring nitrogen opposite the carbonyl group.

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