User:Ericsnis/sandbox

Summary
Exonuclease 3'-5' domain containing 3 (EXD3) in Homo sapiens, synonymous with the gene are LOC54932 and probable exonuclease mut-7 homolog. EXD4 features a domain of unknown function (DUF82) as well as mut-7, a conserved domain and a domain found in Caenorhabditis elegans and other metazoans. EXD3 is located on the long arm of chromosome 9 (9q34.3) at 140.3Kbp directly adjacent to NOXA1 which is NADPH oxidase activator. It does not share sequence with any other known human genes. The nucleotide sequence is 2766bp with a 5' UTR running from 1-196. The coding sequence runs from 197 to 2768 followed by a 3' UTR from 2769 to 2887. The start codon is located nucleotide 136 with a stop codon at nucleotide 2766.

Mut-7 Domain
Mut-7 is implicated in posttranscriptional gene silencing. It contains a DEDDy-type DnaQ-like 3'-5' exonuclease domain possessing three conserved sequence motifs, termed ExoI, ExoII and ExoIII, with a specific YX(3)D pattern at ExoIII. These motifs are clustered around the active site and contain four conserved acidic residues that serve as ligands for the two metal ions required for catalysis. The catalytic site is characterized by the presence of four negatively charged residues (DEDD) that serve as ligands for the two metal ions required for activity.