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RNA Polymerase

RNA Polymerase Model Demonstration Model

Teaching Points

DNA stores the information for building proteins in the cell, but the message must go through an RNA intermediate. The large multi–subunit complex that reads the DNA sequence and creates mRNA is RNA Polymerase (RNAP), found in every living organism. Bacterial RNAP contains 6 subunits (ββ'ααωδ). The ββ' subunits form several distinct functional channels that accommodate double stranded DNA and the RNA–DNA hybrid as well as the exit channel that guides the growing RNA strand out of the complex and the secondary channel that allows nucleotides to enter the active site. This model focuses on the β' subunit that contains the highly conserved active site sequence and several structures involved in the catalytic mechanism. The bridge helix (BH) and trigger loop (TL) work together as a "gate" to enhance the catalytic action by facilitating nucleotide addition. In the crystal structure of the RNAP elongation complex (EC) without NTP in the active site the TL (β' 1236-1265) is unstructured. In the EC crystal structure with a non-hydrolysable nucleotide (AMPcPP) the TL folds into two anti-parallel helices (trigger helix, TH) that interact with the adjacent BH to create a three helical bundle forming a catalytically active complex. The other structures that are functionally important in the β' subunit are the "lid" (β' 526-539) that cleaves the RNA–DNA directing the newly formed RNA out through the exit channel and the "rudder" (β' 586-601) that helps to stabilize the DNA helix and the RNA–DNA hybrid in the active site channel.

Models in this Collection

RNA polymerase beta subunit

 

 

Requesting this Model

Loan Time Frame: 3 weeks

Delivery

  • Use the calendar below to select a three week loan. Available times are shown in green. Select a date one week prior to the date you want the model to arrive. After selecting your time period, select checkout and complete the booking details.
  • This loan includes both delivery and return shipping time. Please make sure to plan time (approximately one week) for us to deliver the model to you. You can expect the model to arrive approximately one week following the first day of the requested loan period.

Pick-Up

  • Use the calendar below to select a three week loan. Available times are shown in green. Select the date you want to pick-up the model. After selecting your time period, select checkout and complete the booking details.

Requesting Other Models

You may schedule one copy of a model for three weeks. Due to limited resources, we are unable to send multiple copies or additional materials.

If you would like to request a loan of a different model for the same time frame you may add this to your cart. Up to three different types of models may be checked out at one time. You will need to fill out a separate request for model loans with a different time frame.

Questions?

Please contact us at cbmloans@msoe.edu with any questions about the lending process or the availability of models.

Contact Margaret Franzen at franzen@msoe.edu or (414) 277-2824 with questions about the models, teaching resources or educational content.

 

Model Documentation and Instructions

Teaching Points and Inventory
Assembling the Model

General Model Information

  • The model is made of plaster with the ZCorp 3D printer.
  • The model is in backbone format.

Returning Models

Models must be returned on or before the due date. Borrowers are responsible for return shipping costs.

Ship models to:
Receiving
Milwaukee School of Engineering
1000 N. Market Street
Milwaukee, WI 53202-3113

Please insure the models for the amount indicated in each suitcase. Any damage incurred in return shipping due to improper packing will be charged to the borrower. We recommend using FedEx or UPS with "two-day ground" transportation. Make sure to get a tracking number for the shipment.

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