1. Elongin from Saccharomyces cerevisiae*
- Author
-
Koth, Christopher M., Botuyan, Maria Victoria, Moreland, Rodney J., Jansma, David B., Conaway, Joan W., Conaway, Ron C., Chazin, Walter J., Friesen, James D., Arrowsmith, Cheryl H., and Edwards, Aled M.
- Abstract
Elongin is a transcription elongation factor that was first identified in mammalian systems and is composed of the three subunits, elongin A, B, and C. Sequence homologues of elongin A and elongin C, but not elongin B, were identified in the yeast genome. Neither yeast elongin A nor C sequence homologues was required for cell viability. The two gene products could be purified from yeast as a complex. A recombinant form of the complex, which could only be produced in bacteria if the gene products were co-expressed, was purified over several chromatographic steps. The complex did not stimulate transcription elongation by yeast RNA polymerase II. Using limited proteolysis, the N-terminal 144 residues of yeast elongin A were shown to be sufficient for interaction with yeast elongin C. The purified complex of yeast elongin C/elongin A1–143was analyzed using circular dichroism and nuclear magnetic spectroscopy. These studies revealed that yeast elongin A is unfolded but undergoes a dramatic modification of its structure in the presence of elongin C, and that elongin C forms a stable dimer in the absence of elongin A.
- Published
- 2000
- Full Text
- View/download PDF