Exonucleases are enzymes (found as individual enzymes, or as parts of larger enzyme complexes) that cleave nucleotides one at a time from an end of a polynucleotide chain. Nucleotides are Organic compounds that consist of three joined structures a nitrogenous base a Sugar, and a Phosphate group These enzymes hydrolyze phosphodiester bonds from either the 3' or 5' terminus of a polynucleotide molecule.
Examples
DNA polymerase I contains a 5' exonuclease that clips off the RNA primer contained immediately upstream from the site of DNA synthesis in a 5' --> 3' manner. DNA Polymerase I (or Pol I) is an Enzyme that participates in the process of DNA replication in Prokaryotes It is composed of 928 amino acids Pol I then synthesizes DNA nucleotides in place of the RNA primer it had just removed. DNA polymerase I also has 3' to 5' exonuclease activity which is used in editing and proofreading DNA for errors.
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. Animals Plants fungi, and Protists are eukaryotes (juːˈkærɪɒt or -oʊt Organisms whose cells are organized into complex The exosome complex (or PM/Scl complex, often just called the exosome) is a multi- Protein complex, capable of degrading various types of An exoribonuclease is an Exonuclease Ribonuclease, which are enzymes that degrade RNA by removing terminal Nucleotides from either the
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exonuclease
-noun
- (biochemistry, genetics) Any of a group of enzymes which cleave single nucleotides from the end of a polynucleotide (DNA or RNA) chain.
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