Solution structure and dynamics of yeast elongin C in complex with a von Hippel-Lindau peptide

Elongin is a transcription elongation factor that stimulates the rate of el ongation by suppressing transient pausing by RNA polymerase II at many site s along the DNA. It is heterotrimeric in mammals, consisting of elongins A, B and C subunits, and bears overall similarity to a class of E3 ubiquitin ligases known as SCF (Skp1-Cdc53 (cullin)-F-box) complexes. A subcomplex of elongins B and C is a target for negative regulation by the von Hippel-Lin dau (VHL) tumor-suppressor protein. Elongin C from Saccharomyces cerevisiae , Elc1, exhibits high sequence similarity to mammalian elongin C. Using NMR spectroscopy we have determined the three-dimensional structure of Elc1 in complex with a human VHL peptide, VHL(157-171), representing the major Elc 1 binding site. The bound VHL peptide is entirely helical. Elc1 utilizes tw o C-terminal helices and an intervening loop to form a binding groove that fits VHL(157-171). Chemical shift perturbation and dynamics analyses reveal that a global conformational change accompanies Elc1/VHL(157-171) complex formation. Moreover, the disappearance of conformational exchange phenomena on the microsecond to millisecond time scale within Elc1 upon VHL peptide binding suggests a role for slow internal motions in ligand recognition. (C ) 2001 Academic Press.