1R7Z:
reference: NMR structures of loop B RNAs from the stem-loop IV domain of the enterovirus internal ribosome entry site: a single C to U substitution drastically changes the shape and flexibility of RNA., Du Z, Ulyanov NB, Yu J, Andino R, James TL, Biochemistry 2004 May 18;43(19):5757-71. PMID: 15134450

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