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“Purification and Characterization of Deinococcus radiodurans Polynucleotide Phosphorylase a phosphate stimulated Mn 2+ ‐dependent nuclease”
Author(s) -
Spence Madison N.,
Uranga Lee,
Lusetti Shelley
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.906.21
Subject(s) - polynucleotide phosphorylase , deinococcus radiodurans , nuclease , exoribonuclease , dna , dna repair , purine nucleoside phosphorylase , rna , polymerase , biochemistry , biology , microbiology and biotechnology , chemistry , enzyme , rnase p , gene , purine
DNA double strand breaks, if unrepaired, pose a threat to the cell because they can cause a wide variety of genetic alteration and apoptosis. Therefore, DNA double‐strand break repair pathways are critical for the survival of all organisms. Deinococcus radiodurans is one of the most radiation resistant organisms known exhibiting a D 10 dose of 10,000 gy. Its survival is attributed to robust DNA repair mechanisms. Previous work with DNA repair proteins has identified a potential interacting partner, Polynucleotide Phosphorylase (PNPase). PNPase was first characterized for its polymerase and phosphorylase activities on RNA, where it is involved in regulating RNA turnover. In its synthetic mode, PNPase is a metal‐dependent template independent single stranded RNA polymerase that adds nucleotide diphosphates (NDPs) onto an existing RNA chain; as well as a Mg 2+ ‐PO 4 ‐dependent RNA phosphorylase. In vitro studies have shown that PNPase can also work on single stranded DNA substrates when manganese is used as a metal cofactor. Our lab is interested in how PNPase activity can be influenced by other DNA repair proteins and vice versa. The purified D. radiodurans PNPase displays the expected DNA degradation activity with phosphate and its NDP‐dependent polymerase activity. However, we have also observed that the enzyme can degrade DNA in the absence of added phosphate suggesting nuclease activity; and that the addition of phosphate stimulates this Mn 2+ ‐dependent nuclease activity. Support or Funding Information R01GM104375