35exonukleaasi

35exonukleaasi is an enzyme classified as a 3' to 5' exonuclease. It catalyzes the hydrolysis of phosphodiester bonds from the 3' end of nucleic acids, releasing nucleoside monophosphates. The enzyme shows a preference for DNA substrates but can also act on RNA under certain conditions. It requires divalent metal ions, typically Mg2+ or Mn2+, for catalysis and exhibits activity across a range of temperatures and pH values.

In structure, 35exonukleaasi is thought to be a monomeric protein of approximately 35 kDa, containing a conserved acidic active-site motif common to many metal-dependent exonucleases. The catalytic mechanism involves coordination of metal ions by conserved acidic residues that activate a water molecule for nucleophilic attack on the phosphodiester backbone.

In biology, 35exonukleaasi has been implicated in DNA repair and quality control during replication, where it can excise mispaired nucleotides or trim DNA ends during processing events. Its activity can contribute to proofreading, end-repair, and turnover of damaged nucleic acids. Regulation of its expression varies by organism and can respond to DNA-damaging stress.

In biotechnology, the enzyme is of interest for controlled exonucleolytic digestion in cloning, sequencing library preparation, and nuclease assays, though practical use depends on its substrate specificity, stability, and robustness under experimental conditions.

See also Exonuclease, DnaQ-like exonuclease, 3' to 5' exonuclease.