text: Arginine fingers often work with other features in their assistance of catalysis. For example, in some trimeric dUTPases, such as those of M. tuberculosis, arginine fingers at the 64th and 140th residue can work with magnesium to cleave dUTP into dUMP and a pyrophosphate. The underlying mechanism of action for this is a nucleophilic attack; the positively charged magnesium ion () pulls on an oxygen of the beta and gamma phosphates to allow water to hydrolyze the bond between the beta and alpha phosphates. The arginine fingers help stabilize the transition state. Arginine fingers often interact with other motifs such as the Walker motifs and to perform catalysis more efficiently.