FIG. 5.

Arterivirus nsp11 cleaves RNA preferentially at uridylates. (A) One micromolar 5′-³²P-labeled synthetic oligoribonucleotide containing a single uridylate (RNAsGUA) or a single cytidylate (RNAsGCA) was incubated with 0.3 μM SARS-CoV nsp15 or 0.6 μM EAV nsp11 at 30°C under standard reaction conditions. Aliquots were taken at different time points, and the reaction products were analyzed by denaturing PAGE and phosphorimager analysis. Cleavage sites and the corresponding products are indicated with arrows. (B) The amount of full-length substrate remaining was quantified, and the percentage of cleaved substrate was plotted as a function of the reaction time. The data points represent mean values from three independent experiments, and the error bars denote standard deviations.