241D:
reference: Extension of the four-stranded intercalated cytosine motif by adenine.adenine base pairing in the crystal structure of d(CCCAAT)., Berger I, Kang C, Fredian A, Ratliff R, Moyzis R, Rich A, Nat Struct Biol 1995 May;2(5):416-25. PMID: 7664099

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