Physiological functions of hydroperoxidases in Rhodobacter capsulatus

Hochman, Ayala; Figueredo, Antonio; Wall, Judy D.

doi:10.1128/jb.174.10.3386-3391.1992

Cited by 32 publications

(24 citation statements)

References 43 publications

(46 reference statements)

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“…Decreases in stationary-phase plating efficiency of several orders of magnitude have been reported for catalase-peroxidase null mutants of Caulobacter crescentus (51) and Rhodobacter capsulatus (27). A similar deficit in stationary-phase survival was found for the L. pneumophila katA null (Fig.…”

Section: Resultssupporting

confidence: 60%

“…Among the others, L. pneumophila CuZnSOD is also periplasmic (52), but the catalase-peroxidases of C. crescentus (51) and R. capsulatus (18,19,27,29) have not been subjected to localization studies and are not predicted to contain a signal peptide (PSORT Prediction, http://psort.nibb.ac.jp/form.html; Signal P V1.1, http://www.cbs.dtu.dk/services/signalP/). Our studies raise the question of whether a periplasmic location is a sine qua non for the stationary-phase function.…”

Section: Discussionmentioning

confidence: 99%

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Catalase-Peroxidases of Legionella pneumophila : Cloning of the katA Gene and Studies of KatA Function

Bandyopadhyay

Steinman

2000

J Bacteriol

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Legionella pneumophila, the causative organism of Legionnaires' pneumonia, contains two enzymes with catalatic and peroxidatic activity, KatA and KatB. To address the issue of redundant, overlapping, or discrete in vivo functions of highly homologous catalase-peroxidases, the gene for katA was cloned and its function was studied in L. pneumophila and Escherichia coli and compared with prior studies of katB in this laboratory. katA is induced during exponential growth and is the predominant peroxidase in stationary phase. When katA is inactivated, L. pneumophila is more sensitive to exogenous hydrogen peroxide and less virulent in the THP-1 macrophage cell line, similar to katB. Catalatic-peroxidatic activity with different peroxidatic cosubstrates is comparable for KatA and KatB, but KatA is five times more active towards dianisidine. In contrast with these examples of redundant or overlapping function, stationary-phase survival is decreased by 100-to 10,000-fold when katA is inactivated, while no change from wild type is seen for the katB null. The principal clue for understanding this discrete in vivo function was the demonstration that KatA is periplasmic and KatB is cytosolic. This stationary-phase phenotype suggests that targets sensitive to hydrogen peroxide are present outside the cytosol in stationary phase or that the peroxidatic activity of KatA is critical for stationary-phase redox reactions in the periplasm, perhaps disulfide bond formation. Since starvation-induced stationary phase is a prerequisite to acquisition of virulence by L. pneumophila, further studies on the function and regulation of katA in stationary phase may give insights on the mechanisms of infectivity of this pathogen.

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Section: Resultssupporting

confidence: 60%

Section: Discussionmentioning

confidence: 99%

Catalase-Peroxidases of Legionella pneumophila : Cloning of the katA Gene and Studies of KatA Function

Bandyopadhyay

Steinman

2000

J Bacteriol

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“…C. crescentus catalase-peroxidase clearly plays a critical role in stationary-phase survival, a role not shared by E. coli katG or katE. In Rhodobacter capsulatus, which contains a catalaseperoxidase and a peroxidase, a mutant lacking the catalaseperoxidase activity shows a decrease in stationary-phase survival similar to that of the C. crescentus katG null mutant (11). However, the responsible gene was not cloned, and changes of expression during growth were not reported.…”

Section: Resultsmentioning

confidence: 99%

Catalase-peroxidase of Caulobacter crescentus: function and role in stationary-phase survival

1997

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Caulobacter crescentus is an obligate aerobe which is exposed to high concentrations of photosynthetic oxygen and low levels of nutrients in its aquatic environment. Physiological studies of oxidative and starvation stresses in C. crescentus were undertaken through a study of lacZ fusion and null mutant strains constructed from the cloned 5 end of katG, encoding a catalase-peroxidase. The katG gene was shown to be solely responsible for catalase and peroxidase activity in C. crescentus. Like the katG of Escherichia coli, C. crescentus katG is induced by hydrogen peroxide and is important in sustaining the exponential growth rate. However, dramatic differences are seen in growth stage induction. E. coli KatE catalase and KatG catalase-peroxidase activities are induced 15-to 20-fold during exponential growth and then approximately halved in the stationary phase. In contrast, C. crescentus KatG activity is constant throughout exponential growth and is induced 50-fold in the stationary phase. Moreover, the survival of a C. crescentus katG null mutant is reduced by more than 3 orders of magnitude after 24 h in stationary phase and more than 6 orders of magnitude after 48 h, a phenotype not seen for E. coli katE and katG null mutants. These results indicate a major role for C. crescentus catalaseperoxidase in stationary-phase survival and raise questions about whether the peroxidatic activity as well as the protective catalatic activity of the dual-function enzyme is important in the response to starvation stress.Caulobacter crescentus is a gram-negative bacterium whose asymmetry of cell division and dimorphic life cycle are subjects of extensive investigation (27). By comparison, little is known about the physiology of Caulobacter. We have been interested in the response of C. crescentus to oxidative stress and starvation (26), salient features of its natural environment. As a freshwater pond bacterium, C. crescentus is frequently associated with cyanobacteria (2, 15), whose photosynthetic activity could expose the bacterium to high oxygen concentrations. As an organism adapted to nutrient-poor conditions (8,21,22), C. crescentus is likely to frequently enter and exit the stationary phase.Catalases and catalase-peroxidases have been studied in the context of oxidative and starvation (stationary phase) stress. Both enzymes catalyze H 2 O 2 decomposition. Stationary-phase induction, especially by catalases, is a hallmark of the multiple stress resistance acquired during starvation (13). Information about these activities in C. crescentus appears to be limited to the demonstration of catalase activity in a plate assay by Poindexter (21, 22) and our recent demonstration that a single catalase-peroxidase is present and is induced during stationary phase (26). The present work was undertaken to study the expression and function of this catalase-peroxidase in response to oxidative stress and during growth. We report here the cloning of the 5Ј end of the katG catalase-peroxidase gene and its constitutive expression during th...

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“…However, these enzymes show properties which are distinct from those of typical catalases in that they possess narrow pH ranges for maximal activity and increased sensitivity to temperature, are inactivated by H202, and are not inhibited by 3-amino-1,2,4-triazole (10,12). Catalase-peroxidase proteins have been observed in the following bacteria: Escherichia coli (3), Rhodopseudomonas capsulata (14), Klebsiella pneumoniae (13), Chromatium vinosum (21), Rhodobacter capsulatus (12), Salmonella typhimurium (18), and the alkalophilic Bacillus strain YN-2000 (28). Therefore, it would appear that some microorganisms contain a novel group of hydroperoxidases which possess both catalase and peroxidase activities and which share characteristics with the typical catalases and peroxidases from higher organisms.…”

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confidence: 99%

Purification of a catalase-peroxidase from Halobacterium halobium: characterization of some unique properties of the halophilic enzyme

Brown‐Peterson

Salin

1993

J Bacteriol

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A hydroperoxidase purified from the halophilic archaeon Halobacterium halobium exhibited both catalase and peroxidase activities, which were greatly diminished in a low-salt environment. Therefore, the purification was carried out in 2 M NaCi. Purified protein exhibited catalase activity over the narrow pH range of 6.0 to 7.5 and exhibited peroxidase activity between pH 6.5 and 8.0. Peroxidase activity was maximal at NaCi concentrations above 1 M, although catalase activity required 2 M NaCI for optimal function. Catalase activity was greatest at 50'C; at 90'C, the enzymatic activity was 20%o greater than at 250C. Peroxidase activity decreased rapidly above its maximum at 40'C. An activation energy of 2.5 kcal (ca. 10 kJ)/mol was calculated for catalase, and an activation energy of 4.0 kcal (ca. 17 kJ)/mol was calculated for peroxidase. Catalase activity was not inhibited by 3-amino-1,2,4-triazole but was inhibited by KCN and NaN3 (apparent KA [KAPP] of 50 and 67.5 FLM, respectively). Peroxidative activity was inhibited equally by KCN and NaN3 (K1APP for both, -30 tiM). The absorption spectrum showed a Soret peak at 404 nm, and there was no apparent reduction by dithionite. A heme content of 1.43 per tetramer was determined. The protein has a pI of 3.8 and an Mr of 240,000 and consists of four subunits of 60,300 each.

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Physiological functions of hydroperoxidases in Rhodobacter capsulatus

Cited by 32 publications

References 43 publications

Catalase-Peroxidases of Legionella pneumophila : Cloning of the katA Gene and Studies of KatA Function

Catalase-Peroxidases of Legionella pneumophila : Cloning of the katA Gene and Studies of KatA Function

Catalase-peroxidase of Caulobacter crescentus: function and role in stationary-phase survival

Purification of a catalase-peroxidase from Halobacterium halobium: characterization of some unique properties of the halophilic enzyme

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