Fig. 2.

Catalytic site of αTAT1 and bisubstrate kinetics. (A) Cartoon representation of the catalytic site of αTAT1. The coloring scheme and labeling is the same as in Fig. 1, with the addition of sulfur colored in magenta. Residues surrounding the catalytic site are labeled for frame of reference. (B) Microtubule acetylation progress curves for WT, C120, and D157 mutant αTAT1. Curves fit to D157 mutants are shown as dashed lines because of a poor fit. (C) Bisubstrate kinetics of αTAT1 acetylation. Experiments were performed at four different AcCoA concentrations, 25, 12, 10, and 5 μM, and a double reciprocal plot of 1/velocity versus 1/[MT] (microtubule) is shown. A best fit of the plot displays a plot with the lines intersecting at a common x-intercept indicative of a ternary complex mechanism.