5D9A:
reference: Crystal structure of the RNA-dependent RNA polymerase from influenza C virus., Hengrung N, El Omari K, Serna Martin I, Vreede FT, Cusack S, Rambo RP, Vonrhein C, Bricogne G, Stuart DI, Grimes JM, Fodor E, Nature. 2015 Nov 5;527(7576):114-7. doi: 10.1038/nature15525. Epub 2015 Oct 26. PMID: 26503046

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