2QS6:
reference: Stabilization by extra-helical thymines of a DNA duplex with Hoogsteen base pairs., Pous J, Urpi L, Subirana JA, Gouyette C, Navaza J, Campos JL, J Am Chem Soc. 2008 May 28;130(21):6755-60. Epub 2008 May 1. PMID: 18447354

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