RNA Polymerase II

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RNAP IIRNAP II

Structural ComponentsStructural Components

The swings to trap the DNA in the cleft. Further along, the sends the DNA template through the cleft in approximately a 90° turn. Both the clamp and wall are parts of the Rpb2 subunit. Further along in the process, the separates the newly synthesized RNA strand from the DNA template. The DNA reforms into a double helix as it leaves RNA pol II.

Other components of RNA pol II include the following: The jaw is the opening through which DNA enters. The funnel is what the NTP’s travel through to be incorporated into the growing RNA strand, and the pore is the end of the funnel. The is an Rpb1 segment that translocates the DNA-RNA combination at the end of each cycle of catalysis. is located within the active site and functions as the catalyst.

Mechanism of ActionMechanism of Action

Alpha AmanitinAlpha Amanitin

α-Amanitin is a bicyclic octapeptide that adheres tightly with RNAP II, which blocks the elongation steps. α-amanitin binds in the funnel and interacts with the bridge helix and adjacent Rpb1, but it does not inhibit the RNA pol II’s interaction with NTP. Instead, α-amanitin likely challenges the bridge’s conformational change that is necessary for the purposed RNAP translocation step. α-Amanitin, found in the poisonous mushroom death cap, leads to death after several days. This time frame aligns with the rate at which mRNA’s and proteins turnover.

ModificationsModifications

General Transcription FactorsGeneral Transcription Factors


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ReferencesReferences

Bushnell, D. A.; Westover, K. D.; Davis, R. E.; Kornberg, R. D. Structural Basis of Transcription: An RNA Polymerase II-TFIIB Cocrystal at 4.5 Angstroms. Science. 2004, 303, 983-988 Cramer, P.; Bushnell, D. A.; Kornberg, R. D. Structural Basis of Transcription: RNA Polymerase II at 2.8 Ångstrom Resolution. Science. 2001, 292, 1863-1876 Uzman, A.; Voet, D. Student companion Fundamentals of biochemistry: life at the molecular level, 4th ed., Donald Voet, Judith G. Voet, Charlotte W. Pratt; John Wiley & amp; Sons, 2012. Evans, D. A.; Fitch, D. M.; Smith, T. E.; Cee, V. J. Application of Complex Aldol Reactions to the Total Synthesis of Phorboxazole B. J. Am. Chem. Soc. 2000, 122, 10033-10046.

NotesNotes

From structural components: Bridge: Depicted: [PDB: 1I6H: 810-845.a] Wall: Depicted: [PDB: 1R5U: 853-919.b; 933-972.b] Clamp: Depicted: [PDB: 1R5U: 3-345.a; 1395-1435.a; 1158-1124.b] Rudder: Depicted: [PDB: 5VVR: 306-321.a]


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This page was created as a final project for the Advanced Biochemistry course at Wabash College during the Fall of 2019. This page was reviewed by Dr. Wally Novak of Wabash College.

Proteopedia Page Contributors and Editors (what is this?)Proteopedia Page Contributors and Editors (what is this?)

Abraham Kiesel, Titus Edwards, James Daniel Andry, Wally Novak, Karsten Theis, Michal Harel