419D:
reference: The crystal structure of the octamer [r(guauaca)dC]2 with six Watson-Crick base-pairs and two 3' overhang residues., Shi K, Biswas R, Mitra SN, Sundaralingam M, J Mol Biol 2000 May 26;299(1):113-22. PMID: 10860726

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