2RF4:
reference: Functional architecture of RNA polymerase I., Kuhn CD, Geiger SR, Baumli S, Gartmann M, Gerber J, Jennebach S, Mielke T, Tschochner H, Beckmann R, Cramer P, Cell. 2007 Dec 28;131(7):1260-72. PMID: 18160037

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