Structure and Mechanism of Staphylococcus aureus TarS, the Wall Teichoic Acid β-glycosyltransferase Involved in Methicillin Resistance
Fig 5
Analysis of TarS catalytic activity.
(A) Comparison of activity in the presence and absence of divalent cations by HPLC based UDP detection. A no protein control was included for reference, and reactions proceeded in the presence of 1mM UDP-GlcNAc and 1mM metal/EDTA where indicated. (B) Relative activities of various TarS catalytic site mutants compared to wild-type by HPLC based UDP detection in the presence of 1mM UDP-GlcNAc. For comparative purposes, relative activity is given as a fraction of wild-type activity whose value was adjusted to 1.0. (C) Thermostability of various TarS catalytic site mutants in the presence and absence of UDP-GlcNAc, analyzed by differential static light scattering as a measure of Tagg upon thermodenaturation. (D) Kinetic parameters of full-length and TarS1-349 constructs. Kinetic parameters were determined using continuous fluorescence-based UDP detection with increasing UDP-GlcNAc concentrations (hydrolysis reaction) or increasing polyRboP concentrations (glycosyltransferase reaction; in presence of 1mM UDP-GlcNAc).