Exonuclease V from Saccharomyces cerevisiae. A 5'----3'-deoxyribonuclease that produces dinucleotides in a sequential fashion.
A novel deoxyribonuclease, exonuclease V, has been purified approximately 30,000-fold from Saccharomyces cerevisiae. Exonuclease V is localized in the nucleus. The nuclease degrades single-stranded, but not double-stranded, DNA from the 5'-end. The products of exonuclease action are dinucleotides, except the 3'-terminal tri- and tetranucleotides which are not degraded. Studies with synthetic oligo- and polynucleotides with specified sequence elements showed that exonuclease V cleaves off dinucleotides as primary digestion products. Thus, the polymers (pT)9pA(pT)n and (pT)10pA(pT)n yielded pTpA and pApT as digestion products, respectively. Removal of the 5'-terminal phosphate from the DNA substrate results in reduced binding of the enzyme to the substrate. In addition, the initial hydrolytic cut by exonuclease V on the dephosphorylated substrate produces a mixture of dinucleoside monophosphates and trinucleoside diphosphates. The enzyme is processive in action.
Burgers
P M
PM
Department of Biological Chemistry, Washington University School of Medicine, St. Louis, Missouri 63110.
Bauer
G A
GA
Tam
L
L
D043211:Exodeoxyribonuclease V; D005090:Exodeoxyribonucleases / Q000378:metabolism*; D006868:Hydrolysis; D007700:Kinetics; D011071:Poly T / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology*
D011071:Poly T; D005090:Exodeoxyribonucleases; D043211:Exodeoxyribonuclease V