AppppA, heat-shock stress, and cell oxidation.

Lee, Philip C.; Bochner, Barry R.; Ames, Bruce N.

doi:10.1073/pnas.80.24.7496

Cited by 334 publications

(200 citation statements)

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“…Therefore, it would appear that organisms might respond in part in a similar fashion to heat and oxidative stress. Additional evidence in support of this hypothesis comes from the observation that a variety of oxidative stresses as well as heat shock induce in bacteria the rapid accumulation of alarmones (4,10,19). A relationship between oxidative stress and heat shock response can be found in the report that Neurospora crassa induces higher levels of peroxidase upon exposure to hyperthermal conditions (9).…”

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confidence: 81%

“…However, the appearance of heat shock proteins is not confined to thermal stress conditions. Oxidative stress, either in the form of exposure of cells to oxygen after brief anaerobiosis or the exposure to substrates which generate active oxy-intermediates, also elicits the synthesis of many heat shock proteins (4,6,10,19). Therefore, it would appear that organisms might respond in part in a similar fashion to heat and oxidative stress.…”

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confidence: 99%

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Elevation of superoxide dismutase in Halobacterium halobium by heat shock

Begonia

Salin

1991

J Bacteriol

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Exposure of Halobacterium halobium to 50°C for 2.5 h in an aerobic environment resulted in a greater than twofold increase in the activity of the manganese-containing superoxide dismutase. Nondenaturing polyacrylamide gels stained for enzymatic activity did not reveal any additional isozymes of superoxide dismutase induced by the heat shock. The maximal effect was observed at 50°C, and the elevated levels of activity remained constant during 5 h of recovery at 40°C. The induction of enzymatic activity was sensitive to protein synthesis inhibitors. The results are discussed relative to heat shock and stress-related proteins as well as alterations in metabolism brought about by elevated temperatures.Following exposure to elevated temperatures, many organisms rapidly synthesize a highly conserved set of proteins termed heat shock proteins (19). Enhanced synthesis of heat-shock proteins has been found in eubacteria and archaebacteria as well as eukaryotes (1,7,20), and their induction appears to correlate with the organism's adaptation to hyperthermal stress (1,19). However, the appearance of heat shock proteins is not confined to thermal stress conditions. Oxidative stress, either in the form of exposure of cells to oxygen after brief anaerobiosis or the exposure to substrates which generate active oxy-intermediates, also elicits the synthesis of many heat shock proteins (4,6,10,19). Therefore, it would appear that organisms might respond in part in a similar fashion to heat and oxidative stress. Additional evidence in support of this hypothesis comes from the observation that a variety of oxidative stresses as well as heat shock induce in bacteria the rapid accumulation of alarmones (4,10,19). A relationship between oxidative stress and heat shock response can be found in the report that Neurospora crassa induces higher levels of peroxidase upon exposure to hyperthermal conditions (9). Finally, a recent report by Privalle and Fridovich (16) (14). Culture flasks were shaken at 150 rpm in a water bath maintained at 40°C. At the middle of the log phase of growth, flasks were removed and transferred to a water bath set at 500C or another designated temperature. After shaking at 150 rpm for 2.5 h at the designated temperature, the flasks were removed and placed once more in the shaking water bath set at 400C. Cells were then allowed to recover for an additional 5 h. Where indicated, various concentrations of inhibitors were added to the culture medium just prior to the initiation of the heat shock. For experiments on cells in still culture, flasks were maintained in a water bath set at 40°C. After the cells reached mid-log phase, the culture flasks were transferred to a 50°C water bath and were maintained there for an additional 2.5 h. Thereafter, the cultures were allowed to recover in a 40°C water bath for 3 h.Aliquots (50 ml) of each culture were taken at the initiation of heat treatment, after the termination of heat treatment, and during phases of recovery. Cells were spun at 7,500 x g for 15 min at 40C and was...

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Elevation of superoxide dismutase in Halobacterium halobium by heat shock

Begonia

Salin

1991

J Bacteriol

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“…dinucleoside polyphosphates (7). The dinucleoside polyphosphate Ap 4 A 1 is induced upon oxidative stress and heat shock both in prokaryotes and eukaryotes (8,9), and the Nudix enzyme subsequently degrades this signaling component to restore the intracellular balance. Experimental data indicate that an increased concentration of Ap 4 A is a signal for cell division in Escherichia coli (10).…”

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confidence: 99%

The NudA Protein in the Gastric Pathogen Helicobacter pylori Is an Ubiquitous and Constitutively Expressed Dinucleoside Polyphosphate Hydrolase

Lundin

Nilsson

Gerhard

et al. 2003

Journal of Biological Chemistry

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The gastric pathogen Helicobacter pylori harbors one Nudix hydrolase, NudA, that belongs to the nucleoside polyphosphate hydrolase subgroup. In this work, the enzymatic activity of purified recombinant NudA protein was analyzed on a number of nucleoside polyphosphates. This predicted 18.6-kDa protein preferably hydrolyzes diadenosine tetraphosphate, Ap 4 A at a k cat of 0.15 s ؊1 and a K m of 80 M, resulting in an asymmetrical cleavage of the molecule into ATP and AMP. To study the biological role of this enzyme in H. pylori, an insertion mutant was constructed. There was a 2-7-fold decrease in survival of the mutant as compared with the wild type after hydrogen peroxide exposure but no difference in survival after heat shock or in spontaneous mutation frequency. Western blot analyses revealed that NudA is constitutively expressed in H. pylori at different growth stages and during stress, which would indicate that this protein has a housekeeping function. Given that H. pylori is a diverse species and that all the H. pylori strains tested in this study harbor the nudA gene and show protein expression, we consider NudA to be an important enzyme in this bacterium.

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“…It binds specifically to a DnaK+ affinity column in a salt-resistant manner and is released in the presence of ATP (36). Intracellular ATP levels appear to fluctuate during the HS response (18), and this fluctuation may be necessary for the induction of thermotolerance (17). The concentration of Hsp7O protein in cells is generally thought to correlate with the degree of thermotolerance (9,21 modulates DnaK activity during the HS response in a manner that is sensitive to the ATP concentration in the cell.…”

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Escherichia coli DnaK and GrpE heat shock proteins interact both in vivo and in vitro

1989

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After being subjected to a sudden rise in temperature, all organisms tested, from Escherichia coli to Homo sapiens, induce the synthesis of a group of so-called heat shock (HS) proteins, some of which are highly conserved among species (for reviews, see references 9, 21, and 25). A number of laboratories have begun to investigate the properties of these proteins and their expression. Regulation of the HS response is understood in part. In E. coli, induction of the HS response occurs at the transcriptional level under the control of the rpoH gene product, a32. The c32 polypeptide allows RNA polymerase enzyme to specifically recognize HS promoters which have a consensus sequence distinct from that recognized by the normal sigma factor, ac70, encoded by rpoD (8,15). One of the negative regulators of the HS response is the DnaK HS protein (30). This 70-kilodalton protein shows approximately 50% amino acid identity with the Hsp7O family of proteins present in all cells examined (4, 9, 21). DnaK and its eucaryotic homologs appear to mediate protein stabilization, refolding, and dissociation (6,19,26). As an example, during initiation of A DNA replication, the DnaK and DnaJ HS proteins, which are essential for A DNA replication, catalyze the ATP-dependent dissociation of A P protein from a complex which includes the X 0, A P, and E. coli DnaB proteins assembled at oriA (20). The A P protein binds to DnaB and inhibits its helicase activity, which is absolutely necessary for the initiation of A DNA replication (20).The E.

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AppppA, heat-shock stress, and cell oxidation.

Cited by 334 publications

References 55 publications

Elevation of superoxide dismutase in Halobacterium halobium by heat shock

Elevation of superoxide dismutase in Halobacterium halobium by heat shock

The NudA Protein in the Gastric Pathogen Helicobacter pylori Is an Ubiquitous and Constitutively Expressed Dinucleoside Polyphosphate Hydrolase

Escherichia coli DnaK and GrpE heat shock proteins interact both in vivo and in vitro

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