6NPW:
reference: Structural determinants for accurate dephosphorylation of RNA polymerase II by its cognate CTD phosphatase during eukaryotic transcription., Irani S, Sipe SN, Yang W, Burkholder NT, Lin B, Sim K, Matthews WL, Brodbelt JS, Zhang Y, J Biol Chem. 2019 Apr 10. pii: RA119.007697. doi: 10.1074/jbc.RA119.007697. PMID: 30971428

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