Figure 2.

HopO1-1 Exhibits mADP-RT Activity.

(A) SDS-PAGE analysis. Recombinant proteins of wild types (HopO1-1 and HopU1), catalytic mutants (HopO1-1^DD and HopU1^DD), and His-MBP were purified with Ni-NTA resin. Purified proteins (2 mM) were separated by SDS-PAGE and stained with SimplyBlue SafeStain. Minus (–) indicates His-MBP only. Numbers on the left indicate molecular mass in kilodaltons.

(B) In vitro ADP-ribosylation assay. Recombinant proteins were incubated with poly-l-Arg to examine their ribosyltransferase activity. His-MBP served as a negative control. Error bars represent se from four reactions. Statistical differences between different recombinant proteins and His-MBP were analyzed with a two-tailed t test (*, P < 5 × 10⁻²; **, P < 5 × 10⁻³). Minus (–) indicates His-MBP only.