4ZNP:
reference: Global RNA Fold and Molecular Recognition for a pfl Riboswitch Bound to ZMP, a Master Regulator of One-Carbon Metabolism., Ren A, Rajashankar KR, Patel DJ, Structure. 2015 Aug 4;23(8):1375-81. doi: 10.1016/j.str.2015.05.016. Epub 2015, Jun 25. PMID: 26118534

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