4PZ7:
reference: How an mRNA capping enzyme reads distinct RNA polymerase II and Spt5 CTD phosphorylation codes., Doamekpor SK, Sanchez AM, Schwer B, Shuman S, Lima CD, Genes Dev. 2014 Jun 15;28(12):1323-36. doi: 10.1101/gad.242768.114. PMID: 24939935

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