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Nucleoside Triphosphate Pyrophosphohydrolase (EC 3.6.1.8) MazG-like domain superfamily This superfamily contains enzymes that hydrolyze the alpha-beta phosphodiester bond of all canonical NTPs into monophosphate derivatives and pyrophosphate (PPi). Divalent ions, such as Mg2+ ion(s), are essential to activate a proposed water nucleophile and stabilize the charged intermediates to facilitate catalysis. These enzymes share a conserved divalent ion-binding motif EXX[E/D] in their active sites. They also share a highly conserved four-helix bundle, where one face forms the active site, while the other participates in oligomer assembly. The four-helix bundle consists of two central antiparallel alpha-helices that can be contained within a single protomer or form upon dimerization. The superfamily members include dimeric dUTP pyrophosphatases (dUTPases; EC 3.6.1.23), the nonspecific NTP-PPase MazG proteins, HisE-encoded phosphoribosyl ATP pyrophosphohydolase (PRA-PH), fungal histidine biosynthesis trifunctional proteins, and several uncharacterized protein families. |
Jiyao W et al.(2023). "The conserved domain database in 2023.",