1EKD:
reference: Nuclear magnetic resonance spectroscopy and molecular modeling reveal that different hydrogen bonding patterns are possible for G.U pairs: one hydrogen bond for each G.U pair in r(GGCGUGCC)(2) and two for each G.U pair in r(GAGUGCUC)(2)., Chen X, McDowell JA, Kierzek R, Krugh TR, Turner DH, Biochemistry 2000 Aug 1;39(30):8970-82. PMID: 10913310

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