title: Elongin from Saccharomyces cerevisiae.
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 A(1-143) was 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.
authors.affiliation: Department of Medical Genetics and Microbiology, University of Toronto, Toronto, Ontario M5S 1A8.
authors.forename: C M
authors.initials: CM
authors.lastname: Koth
authors.forename: M V
authors.initials: MV
authors.lastname: Botuyan
authors.forename: R J
authors.initials: RJ
authors.lastname: Moreland
authors.forename: D B
authors.initials: DB
authors.lastname: Jansma
authors.forename: J W
authors.initials: JW
authors.lastname: Conaway
authors.forename: R C
authors.initials: RC
authors.lastname: Conaway
authors.forename: W J
authors.initials: WJ
authors.lastname: Chazin
authors.forename: J D
authors.initials: JD
authors.lastname: Friesen
authors.forename: C H
authors.initials: CH
authors.lastname: Arrowsmith
authors.forename: A M
authors.initials: AM
authors.lastname: Edwards
mesh_terms: D000595:Amino Acid Sequence; D002942:Circular Dichroism; D019281:Dimerization; D000075065:Elongin; D005656:Fungal Proteins / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D012441:Saccharomyces cerevisiae / Q000737:chemistry*; D014157:Transcription Factors / Q000737:chemistry* / Q000302:isolation & purification; D014158:Transcription, Genetic
chemical_list: D000075065:Elongin; D005656:Fungal Proteins; D014157:Transcription Factors