A DNA endonuclease isolated from yeast nuclear extract

1978 ◽  
Vol 56 (3) ◽  
pp. 181-189 ◽  
Author(s):  
Douglas W. Bryant ◽  
Robert H. Haynes
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Molecular Weight ◽  
Dna Repair ◽  
Nuclear Extract ◽  
Dna Duplexes ◽  
Replicative Form ◽  
Yeast Saccharomyces Cerevisiae ◽  
Dna Endonuclease ◽  
Circular Dna ◽  
Dna Substrate

We have isolated and partially purified a DNA endonuclease from nuclei of the yeast Saccharomyces cerevisiae. Although purified on the basis of its ability to degrade denatured DNA, the enzyme can also attack native DNA. Denatured oligonucleotide products of the enzyme are sensitive to venom phosphodiesterase (EC 3.1.4.1) but not to bovine spleen phosphodiesterase (EC 3.1.4.18). The enzyme has an estimated molecular weight of 6.6–7.5 × 104, more than twice as large as the endonucleases involved in DNA repair in Escherichia coli.When analyzed on glycerol gradients, the endonuclease sedimented as a single activity against both denatured DNA and closed circular DNA duplexes. The enzyme showed a 10-fold preference for denatured over native T7 DNA substrate, and appears to produce random nicks in a supercoiled replicative form of [Formula: see text] DNA (RFI) with no discernable preference for the unpaired bases in the supercoiled duplex. The endonuclease appears to be distinct from the yeast endonucleases previously described.

scholarly journals The essential DNA polymerases delta and epsilon are involved in repair of UV-damaged DNA in the yeast Saccharomyces cerevisiae.

1999 ◽  
Vol 46 (2) ◽  
pp. 289-298 ◽  
Author(s):  
A Hałas ◽  
Z Policińska ◽  
H Baranowska ◽  
W J Jachymczyk
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Repair ◽  
Uv Irradiation ◽  
Dna Polymerases ◽  
Relative Molecular Mass ◽  
Yeast Saccharomyces Cerevisiae ◽  
Strand Breaks ◽  
Single Strand Breaks ◽  
Mutant Strains ◽  
Cellular Dna

We have studied the ability of yeast DNA polymerases to carry out repair of lesions caused by UV irradiation in Saccharomyces cerevisiae. By the analysis of postirradiation relative molecular mass changes in cellular DNA of different DNA polymerases mutant strains, it was established that mutations in DNA polymerases delta and epsilon showed accumulation of single-strand breaks indicating defective repair. Mutations in other DNA polymerase genes exhibited no defects in DNA repair. Thus, the data obtained suggest that DNA polymerases delta and epsilon are both necessary for DNA replication and for repair of lesions caused by UV irradiation. The results are discussed in the light of current concepts concerning the specificity of DNA polymerases in DNA repair.

PURIFICATION AND PROPERTIES OF AN INDUCIBLE β-GLUCOSIDASE OF BAKERS' YEAST

1966 ◽  
Vol 44 (8) ◽  
pp. 1099-1108 ◽  
Author(s):  
A. N. Inamdar ◽  
J. G. Kaplan
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Molecular Weight ◽  
Hydrolytic Activity ◽  
Chromogenic Substrate ◽  
Yeast Saccharomyces Cerevisiae ◽  
Intact Cells ◽  
Highly Active ◽  
Naturally Occurring ◽  
Purification And Properties ◽  
Competitive Inhibitors

The inducible β-glucosidase present in crude extracts of cellobiose-grown bakers' yeast (Saccharomyces cerevisiae C) was purified 50-fold and found to be homogeneous in the ultracentrifuge, with a molecular weight of 313,000. The enzyme was virtually identical in its properties with the internal, cryptic enzyme of the yeast cell, revealed by butanol treatment of the suspensions. It was unlike the membrane-localized enzyme found at the surface of intact cells in its low affinity for cellobiose and methyl-β-glucoside as substrates and inhibitors. The enzyme was specific for the β configuration and had no activity against substrates such as α-glucosides, β-galactosides, or β-xylosides. It was highly active against both naturally occurring and synthetic substrates with aromatic aglycones, and may thus be classed as an aryl-β-glucosidase. The enzyme had weak hydrolytic activity against methyl-β-glucoside and cellobiose, but these compounds, unlike all of the aryl-β-glucosides tested, were not competitive inhibitors of its activity against the chromogenic substrate pNPG. There were about 40,000 molecules of enzyme per cell in fully induced cultures and the enzyme represented about 3% of the total protein of these cells.

The role of PSO and SNM genes in DNA repair of the yeast Saccharomyces cerevisiae

1990 ◽  
Vol 18 (5) ◽  
pp. 387-393 ◽  
Author(s):  
Jo�o A. P. Henriques ◽  
Martin Brendel
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Dna Repair ◽  
Yeast Saccharomyces Cerevisiae

scholarly journals Apparent endocytosis of fluorescein isothiocyanate-conjugated dextran by Saccharomyces cerevisiae reflects uptake of low molecular weight impurities, not dextran.

1987 ◽  
Vol 105 (5) ◽  
pp. 1981-1987 ◽  
Author(s):  
R A Preston ◽  
R F Murphy ◽  
E W Jones
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Molecular Weight ◽  
Lucifer Yellow ◽  
Ph Dependence ◽  
Fluid Phase ◽  
Fluorescein Isothiocyanate ◽  
Low Molecular Weight ◽  
Yeast Saccharomyces Cerevisiae ◽  
Fluid Phase Endocytosis ◽  
Rapid Kinetics

Concurrent with Riezman's report (Riezman, H. 1985, Cell. 40:1001-1009) that fluid-phase endocytosis of the small molecule Lucifer yellow occurs in the yeast Saccharomyces cerevisiae, Makarow (Makarow, M. 1985. EMBO [Eur. Mol. Biol. Organ.] J. 4:1861-1866) reported the endocytotic uptake of 70-kD FITC-dextran (FD) and its subsequent compartmentation into the yeast vacuole. Samples of FD synthesized and purified here failed to label yeast vacuoles under conditions that allowed labeling using commercial FD. Chromatography revealed that the commercial FD was heavily contaminated with at least three low molecular weight fluorescent compounds. Dialysis was ineffective for removing the contaminants. After purification (Sephadex G25, ethanol extraction), commercial FD was incapable of labeling vacuoles. Extracts of cells labeled with partially purified FD contained FITC, not FD, based on Sephadex and thin layer chromatography. In either the presence or absence of unlabeled 70-kD dextran, authentic FITC (10 micrograms/ml) was an effective labeling agent for vacuoles. The rapid kinetics (0.28 pmol/min per 10(6) cells at pH 5.5) and the pH dependence of FITC uptake suggest that the mechanism of FITC uptake involves diffusion rather than endocytosis. In view of these results, labeling experiments that use unpurified commercial FD should be interpreted with caution.

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