Changes in the structure of the dimeric C-terminal domain of the Raus sarcoma virus with mutation. D155Y-CTD is a lethal mutation that is not infective and does not dimerize. R185W-CTD has a 20-fold tighter dimerization affinity and is nearly as infective as WT-CTD. The double mutant D155Y/R185W-CTD has a dimerization affinity that is 10 fold weaker than WT-CTD and is weakly infective. These panels show the chemical shift index change for each residue on the structure of the dimeric protein. Chemical shift changes were calculated using the following expression, sqrt[(deltaH)^2+(deltaN/5)^2], where deltaH and deltaN are the chemical shift differences between the WT and the mutant proteins (D155Y-CTD, R185W-CTD, D155Y/R185W-CTD) or between the double mutant protein and the lethal mutant protein (D155Y/R185W-CTD – D155Y-CTD). Index values greater than 0.2 are colored red, and a color gradient from red to blue was used between 0.2 and 0. Most changes are either local in sequence or structure to the mutation site, and the effects of the mutations on structure appear to be nearly perfectly additive.
Images provided by Ropson Lab.