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- * 3.6. Adenine or cytosine: M
- *
- * There are few common features between A and C. The presence of an NH2
- * group in similar positions on both bases (Fig. 1) makes possible a
- * logically derived symbol. A and N being ruled out, M (from aMino) is
- * recommended.
- *
- *
- * Fig. 1. Origin of the symbols M and K The four bases are drawn so as to
- * show the relationship between adenine and cytosine on the one hand, which
- * both have aMino groups at the ring position most distant from the point
- * of attachment to the sugar, and between guanine and thymine on the other,
- * which both have Keto groups at the corresponding position. The ring atoms
- * are numbered as recommended [24-26], although for the present purpose
- * this has the disadvantage of giving discordant numbers to the
- * corresponding positions.
- */