Exonuclease 3'-5' Domain Containing Protein 3 (EXD3)

EXD3 belongs to the mut-7 family.. contains 1 3'-5' exonuclease domain. Exonucleases are enzymes that work by cleaving nucleotides one at a time from the end of a polynucleotide chain. A hydrolyzing reaction that breaks phosphodiester bonds at either the 3’ or the 5’ end occurs. Its close relative is the endonuclease, which cleaves phosphodiester bonds in the middle of a polynucleotide chain. Eukaryotes and prokaryotes have three types of exonucleases involved in the normal turnover of mRNA: 3’ to 5’ exonuclease, which is a dependent decapping protein, 5’ to 3’ exonuclease, an independent protein, and poly(A)-specific 3’ to 5’ exonuclease. In both archaebacteria and eukaryotes, one of the main routes of RNA degradation is performed by the multi-protein exosome complex, which consists largely of 3' to 5' exoribonucleases.