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Elongin from Saccharomyces cerevisiae.
C M Koth1, M V Botuyan, R J Moreland
1Department of Medical Genetics and Microbiology, University of Toronto, Toronto, Ontario M5S 1A8.
The Journal of Biological Chemistry
|February 7, 2001
Summary
Yeast elongin A and C form a complex essential for structural changes, though not required for cell viability. This complex did not enhance yeast transcription elongation by RNA polymerase II.
Area of Science:
- Molecular Biology
- Biochemistry
Background:
- Elongin, a transcription elongation factor, comprises three subunits: elongin A, B, and C.
- Homologues of elongin A and C, but not B, exist in yeast.
- Yeast elongin A and C are non-essential for cell viability.
Purpose of the Study:
- To investigate the interaction and structural properties of yeast elongin A and C.
- To determine the role of the yeast elongin complex in transcription elongation.
Main Methods:
- Purification of yeast elongin A and C complex.
- Recombinant complex production in bacteria.
- Limited proteolysis to identify interaction domains.
- Circular dichroism and nuclear magnetic resonance spectroscopy for structural analysis.
Main Results:
- Yeast elongin A and C can be purified as a complex.
- The complex did not stimulate yeast RNA polymerase II-mediated transcription.
- The N-terminal 144 residues of yeast elongin A mediate interaction with elongin C.
- Yeast elongin A is unfolded but structurally modified upon binding elongin C.
- Elongin C forms a stable dimer independently.
Conclusions:
- Yeast elongin A and C form a stable complex with distinct structural properties.
- The yeast elongin complex does not appear to function as a transcription elongation factor for RNA polymerase II.
- Elongin C's dimerization and elongin A's structural changes highlight subunit-specific roles.