Nudix family

The Nudix family is a protein family of phosphohydrolases. Using water-mediated catalysis they break a phosphate bond in their substrate to create two products. Substrates hydrolysed by Nudix enzymes comprise a wide range of organic pyrophosphates, including nucleoside di- and triphosphates, dinucleoside and diphosphoinositol polyphosphates, nucleotide sugars and RNA caps, with varying degrees of substrate specificity. Nudix stands for Nucleoside Diphosphate linked to X. There are two components to the Nudix family: the so-called Nudix fold of a beta sheet with alpha helices on each side and the Nudix motif which contains catalytic and metal-binding amino acids. The Nudix motif is GXXXXXEXXXXXXXREUXEEXGU where U is Isoleucine, Leucine, or Valine and X is any amino acid. This forms a short helix which (usually) contains the catalytic amino acids. Nudix family enzymes include Dcp2 of the decapping complex, ADP-ribose diphosphatase, MutT, ADPRase, Ap4A, RppH, and many others.