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The cytoplasmic Cu,Zn superoxide dismutase of saccharomyces cerevisiae is required for resistance to freeze-thaw stress. Generation of free radicals during freezing and thawing. J Biol Chem 1998 Sep 04;273(36):22921-8

Date

08/29/1998

Pubmed ID

9722512

DOI

10.1074/jbc.273.36.22921

Scopus ID

2-s2.0-0032483373 (requires institutional sign-in at Scopus site)   124 Citations

Abstract

The involvement of oxidative stress in freeze-thaw injury to yeast cells was analyzed using mutants defective in a range of antioxidant functions, including Cu,Zn superoxide dismutase (encoded by SOD1), Mn superoxide dismutase (SOD2), catalase A, catalase T, glutathione reductase, gamma-glutamylcysteine synthetase and Yap1 transcription factor. Only those affecting superoxide dismutases showed decreased freeze-thaw tolerance, with the sod1 mutant and the sod1 sod2 double mutant being most affected. This indicated that superoxide anions were formed during freezing and thawing. This was confirmed since the sod1 mutant could be made more resistant by treatment with the superoxide anion scavenger MnCl2, or by freezing in the absence of oxygen, or by the generation of a rho0 petite. Increased expression of SOD2 conferred freeze-thaw tolerance on the sod1 mutant indicating the ability of the mitochondrial superoxide dismutase to compensate for the lack of the cytoplasmic enzyme. Free radicals generated as a result of freezing and thawing were detected in cells directly using electron paramagnetic resonance spectroscopy with either alpha-phenyl-N-tert-butylnitrone or 5, 5-dimethyl-1-pyrroline-N-oxide as spin trap. Highest levels were formed in the sod1 and sod1 sod2 mutant strains, but lower levels were detected in the wild type. The results show that oxidative stress causes major injury to cells during aerobic freezing and thawing and that this is mainly initiated in the cytoplasm by an oxidative burst of superoxide radicals formed from oxygen and electrons leaked from the mitochondrial electron transport chain.

Author List

Park JI, Grant CM, Davies MJ, Dawes IW

Author

Jong-In Park PhD Professor in the Biochemistry department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Copper
Cytoplasm
DNA-Binding Proteins
Freezing
Glutamate-Cysteine Ligase
Glutathione Reductase
Oxidative Stress
Oxygen
Reactive Oxygen Species
Saccharomyces cerevisiae
Saccharomyces cerevisiae Proteins
Superoxide Dismutase
Superoxide Dismutase-1
Transcription Factors
Zinc