Elongin from Saccharomyces cerevisiae.
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.
Koth
C M
CM
Department of Medical Genetics and Microbiology, University of Toronto, Toronto, Ontario M5S 1A8.
Botuyan
M V
MV
Moreland
R J
RJ
Jansma
D B
DB
Conaway
J W
JW
Conaway
R C
RC
Chazin
W J
WJ
Friesen
J D
JD
Arrowsmith
C H
CH
Edwards
A M
AM
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
D000075065:Elongin; D005656:Fungal Proteins; D014157:Transcription Factors