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A single-stranded DNA exonuclease from Schizosaccharomyces pombe
1Fred Hutchinson Cancer Research Center, Seattle, Washington 98104.
Biochemistry
|July 28, 1992
Summary
Researchers purified a novel DNA exonuclease II (ExoII) from yeast cells. This enzyme degrades single-stranded DNA, suggesting a role in DNA repair and genetic recombination processes.
Area of Science:
- Molecular Biology
- Biochemistry
- Genetics
Background:
- Meiotic cells of Schizosaccharomyces pombe are crucial for genetic recombination.
- DNA repair mechanisms are essential for maintaining genomic stability.
- Specific nucleases play vital roles in DNA metabolism.
Purpose of the Study:
- To purify and characterize a novel DNA exonuclease from Schizosaccharomyces pombe.
- To investigate the enzymatic properties and potential biological functions of the purified enzyme.
Main Methods:
- Purification of DNA exonuclease to near homogeneity from meiotic cells.
- Determination of molecular weight and substrate specificity.
- Kinetic analysis to determine Km for 5' DNA ends.
Main Results:
- A DNA exonuclease, designated exonuclease II (ExoII), was purified.
- ExoII has an apparent molecular weight of 134,000 and is abundant.
- The enzyme specifically degrades single-stranded DNA 5' to 3' with high affinity (Km = 3.6 x 10(-11) M).
- Degradation produces 5' deoxynucleoside monophosphates.
Conclusions:
- Exonuclease II (ExoII) from Schizosaccharomyces pombe exhibits properties similar to E. coli RecJ protein.
- ExoII likely plays a role in genetic recombination and DNA damage repair pathways in yeast.