Figure 6.

(A) Zinc binding in wild-type and mutant derivatives of I-TevIII. The presence of zinc was determined by incubating 5 nmol of each protein with PAR, and the amount of zinc released in the presence of MMTS was measured as the increase in absorbance at 500 nm. The data represent the means ± standard errors of three independent measurements. (B) Schematic of the I-TevIII proteins used for the PAR analysis. The consensus sequence for the two tandem zinc fingers (ZF) is shown, with horizontal lines indicating the extent of proteins present in the N-terminal deletions 96C and 194C.