Biophysical and enzymatic characterization of lid domain mutants.

ATPase activities were determined in standard buffer as described in the Materials and Methods section. The KM-determination was carried out at 2 µM protein concentration and curves showed very tight binding and full saturation at stoichiometric concentrations, implying that the KM value is smaller than or around 2 µM. Consequently, Michaelis-Menten conditions are not maintained and a determination of an apparent KD value is not permitted by this experimental setup (indicated by “tight”). KD denotes the apparent affinity. The errors represent standard deviations of three independent experiments.