4RHD:
reference: Evolution of functional six-nucleotide DNA., Zhang L, Yang Z, Sefah K, Bradley KM, Hoshika S, Kim MJ, Kim HJ, Zhu G, Jimenez E, Cansiz S, Teng IT, Champanhac C, McLendon C, Liu C, Zhang W, Gerloff DL, Huang Z, Tan W, Benner SA, J Am Chem Soc. 2015 Jun 3;137(21):6734-7. doi: 10.1021/jacs.5b02251. Epub 2015, May 20. PMID: 25966323

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