Figure 6.

The role of uridylylated PII and GlnK in stimulation of deadenylylation activity of ATase. Homotrimeric PII-UMP is a potent stimulant (signified by large plus) of the ATases deadenylylation activity whereas under the same in vitro conditions homotrimeric GlnK-UMP is almost completely inactive even when present in two-fold excess together with homotrimeric PII-UMP. The PII-UMP/GlnK-UMP heterotrimers appear to be able to stimulate the deadenylylation activity to lower extent (signified by small plus sign).