Humboldt State University ® Department of Chemistry

Richard A. Paselk

Chem 432	Biochemistry	Spring 2002
	© R. Paselk 2002
	Discussion

Clinical Case Studies/Discussion Topics-7

The Determination of Protein Structure at the Atomic Level

Note that x-ray diffraction and diptheria are discussed in Voet, Voet & Pratt making it a good place to start!

Discussion Topic I: Determination of the Yeast RNA Polymerase II Structure by Electron Crystallography*. Find the article: S.A. Darst et. al. (1991) "Three-Dimensional Structure of Yeast RNA Ploymerase II at 16 Å Resolution." Cell 66, 121-128. Be able to discuss the following questions:

• What is the composition of this enzyme?
• How was the structure of this molecule determined in this study?
  • What kind of equipment was used?
  • What kind of data were acquired?
  • How was the data reduced to generate an image?
• What advantages might this method have over X-ray diffraction?
• What can we say about the activity of this enzyme in terms of its structure in this study?

Discussion Topic II: Determination of the Yeast RNA Polymerase II Structure by X-ray Crystallography. Find the article: Patrick Cramer et. al. (28 April 2000) "Architecture of RNA Polymerase II and Implications for the Transcription Mechanism." Science, 288: 640-649. Be able to discuss the following questions:

• How was the structure of this molecule determined in this study?
  • What kind of equipment was used?
  • What kind of data were acquired?
  • How was the data reduced to generate an image?
• How did this study build on the earlier work of Darst et.al. above?
• How does the resolution of the techniques of Electron and X-ray Crystallography compare?
• What advantages does this method have over electron crystallography?

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*RNA pol II was reviewed in Ann. Rev. Biochem. 60, 689­715 (1991).

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Last modified 3 March 2002