scholarly journals Maturation of Rhodobacter capsulatus Multicopper Oxidase CutO Depends on the CopA Copper Efflux Pathway and Requires the cutF Product

2021 ◽  
Vol 12 ◽  
Author(s):  
Yavuz Öztürk ◽  
Crysten E. Blaby-Haas ◽  
Noel Daum ◽  
Andreea Andrei ◽  
Juna Rauch ◽  
...  
Keyword(s):  
Rhodobacter Capsulatus ◽  
Growth Conditions ◽  
Anaerobic Growth ◽  
Binding Motif ◽  
Catalytic Center ◽  
Domains Of Life ◽  
Cu Homeostasis ◽  
Cu Resistance ◽  
Efflux Pathway ◽  
Detoxification Pathway

Copper (Cu) is an essential cofactor required for redox enzymes in all domains of life. Because of its toxicity, tightly controlled mechanisms ensure Cu delivery for cuproenzyme biogenesis and simultaneously protect cells against toxic Cu. Many Gram-negative bacteria contain extracytoplasmic multicopper oxidases (MCOs), which are involved in periplasmic Cu detoxification. MCOs are unique cuproenzymes because their catalytic center contains multiple Cu atoms, which are required for the oxidation of Cu1+ to the less toxic Cu2+. Hence, Cu is both substrate and essential cofactor of MCOs. Here, we investigated the maturation of Rhodobacter capsulatus MCO CutO and its role in periplasmic Cu detoxification. A survey of CutO activity of R. capsulatus mutants with known defects in Cu homeostasis and in the maturation of the cuproprotein cbb3-type cytochrome oxidase (cbb3-Cox) was performed. This revealed that CutO activity is largely independent of the Cu-delivery pathway for cbb3-Cox biogenesis, except for the cupric reductase CcoG, which is required for full CutO activity. The most pronounced decrease of CutO activity was observed with strains lacking the cytoplasmic Cu chaperone CopZ, or the Cu-exporting ATPase CopA, indicating that CutO maturation is linked to the CopZ-CopA mediated Cu-detoxification pathway. Our data demonstrate that CutO is important for cellular Cu resistance under both aerobic and anaerobic growth conditions. CutO is encoded in the cutFOG operon, but only CutF, and not CutG, is essential for CutO activity. No CutO activity is detectable when cutF or its putative Cu-binding motif are mutated, suggesting that the cutF product serves as a Cu-binding component required for active CutO production. Bioinformatic analyses of CutF-like proteins support their widespread roles as putative Cu-binding proteins for several Cu-relay pathways. Our overall findings show that the cytoplasmic CopZ-CopA dependent Cu detoxification pathway contributes to providing Cu to CutO maturation, a process that strictly relies on cutF.

scholarly journals Structural and Functional Analyses of Photosynthetic Regulatory Genes regA and regBfrom Rhodovulum sulfidophilum, Roseobacter denitrificans, and Rhodobacter capsulatus

1999 ◽  
Vol 181 (14) ◽  
pp. 4205-4215 ◽  
Author(s):  
Shinji Masuda ◽  
Yumi Matsumoto ◽  
Kenji V. P. Nagashima ◽  
Keizo Shimada ◽  
Kazuhito Inoue ◽  
...  
Keyword(s):  
Photosynthetic Bacteria ◽  
Rhodobacter Capsulatus ◽  
Photosynthetic Apparatus ◽  
Anaerobic Growth ◽  
Binding Motif ◽  
Sequence Information ◽  
Sensor Kinase ◽  
Rhodovulum Sulfidophilum ◽  
High Level ◽  
Aerobic And Anaerobic

ABSTRACT Genes coding for putative RegA, RegB, and SenC homologues were identified and characterized in the purple nonsulfur photosynthetic bacteria Rhodovulum sulfidophilum and Roseobacter denitrificans, species that demonstrate weak or no oxygen repression of photosystem synthesis. This additional sequence information was then used to perform a comparative analysis with previously sequenced RegA, RegB, and SenC homologues obtained fromRhodobacter capsulatus and Rhodobacter sphaeroides. These are photosynthetic bacteria that exhibit a high level of oxygen repression of photosystem synthesis controlled by the RegA-RegB two-component regulatory system. The response regulator, RegA, exhibits a remarkable 78.7 to 84.2% overall sequence identity, with total conservation within a putative helix-turn-helix DNA-binding motif. The RegB sensor kinase homologues also exhibit a high level of sequence conservation (55.9 to 61.5%) although these additional species give significantly different responses to oxygen. ARhodovulum sulfidophilum mutant lacking regA orregB was constructed. These mutants produced smaller amounts of photopigments under aerobic and anaerobic conditions, indicating that the RegA-RegB regulon controls photosynthetic gene expression in this bacterium as it does as in Rhodobacterspecies. Rhodobacter capsulatus regA- orregB-deficient mutants recovered the synthesis of a photosynthetic apparatus that still retained regulation by oxygen tension when complemented with reg genes fromRhodovulum sulfidophilum and Roseobacter denitrificans. These results suggest that differential expression of photosynthetic genes in response to aerobic and anaerobic growth conditions is not the result of altered redox sensing by the sensor kinase protein, RegB.

scholarly journals The CopA2-Type P1B-Type ATPase CcoI Serves as Central Hub for cbb3-Type Cytochrome Oxidase Biogenesis

2021 ◽  
Vol 12 ◽  
Author(s):  
Andreea Andrei ◽  
Maria Agostina Di Renzo ◽  
Yavuz Öztürk ◽  
Alexandra Meisner ◽  
Noel Daum ◽  
...  
Keyword(s):  
Cytochrome Oxidase ◽  
Metal Binding ◽  
Binding Sites ◽  
Rhodobacter Capsulatus ◽  
Metal Transporters ◽  
Supported Membrane ◽  
Metal Binding Sites ◽  
Domains Of Life ◽  
Cu Homeostasis

Copper (Cu)-transporting P1B-type ATPases are ubiquitous metal transporters and crucial for maintaining Cu homeostasis in all domains of life. In bacteria, the P1B-type ATPase CopA is required for Cu-detoxification and exports excess Cu(I) in an ATP-dependent reaction from the cytosol into the periplasm. CopA is a member of the CopA1-type ATPase family and has been biochemically and structurally characterized in detail. In contrast, less is known about members of the CopA2-type ATPase family, which are predicted to transport Cu(I) into the periplasm for cuproprotein maturation. One example is CcoI, which is required for the maturation of cbb3-type cytochrome oxidase (cbb3-Cox) in different species. Here, we reconstituted purified CcoI of Rhodobacter capsulatus into liposomes and determined Cu transport using solid-supported membrane electrophysiology. The data demonstrate ATP-dependent Cu(I) translocation by CcoI, while no transport is observed in the presence of a non-hydrolysable ATP analog. CcoI contains two cytosolically exposed N-terminal metal binding sites (N-MBSs), which are both important, but not essential for Cu delivery to cbb3-Cox. CcoI and cbb3-Cox activity assays in the presence of different Cu concentrations suggest that the glutaredoxin-like N-MBS1 is primarily involved in regulating the ATPase activity of CcoI, while the CopZ-like N-MBS2 is involved in Cu(I) acquisition. The interaction of CcoI with periplasmic Cu chaperones was analyzed by genetically fusing CcoI to the chaperone SenC. The CcoI-SenC fusion protein was fully functional in vivo and sufficient to provide Cu for cbb3-Cox maturation. In summary, our data demonstrate that CcoI provides the link between the cytosolic and periplasmic Cu chaperone networks during cbb3-Cox assembly.

scholarly journals Acute Peritonitis Caused by Propionibacterium Acnes in a Peritoneal Dialysis Patient

2017 ◽  
Vol 15 (1) ◽  
pp. 33-34
Author(s):  
Nikolina Basic-Jukic ◽  
Vesna Furic-Cunko ◽  
Ivana Juric ◽  
Lea Katalinic ◽  
Ana Rukavina ◽  
...  
Keyword(s):  
Peritoneal Dialysis ◽  
Human Skin ◽  
Dialysis Patient ◽  
Propionibacterium Acnes ◽  
Peritoneal Dialysis Patient ◽  
Growth Conditions ◽  
Anaerobic Growth ◽  
Gram Positive ◽  
Acute Peritonitis ◽  
Clinical Conditions

AbstractPropionibacterium acnes is a gram-positive human skin commensal that is involved in the pathogenesis of acne and prefers anaerobic growth conditions. It has been considered as a low virulence pathogen in different clinical conditions. We present the case of acute peritonitis caused by Propionibacterium acnes in a peritoneal dialysis patient.

scholarly journals Computation of condition-dependent proteome allocation reveals variability in the macro and micro nutrient requirements for growth

2020 ◽  
Author(s):  
Colton J. Lloyd ◽  
Jonathan Monk ◽  
Laurence Yang ◽  
Ali Ebrahim ◽  
Bernhard O. Palsson
Keyword(s):  
Amino Acids ◽  
Growth Conditions ◽  
Anaerobic Growth ◽  
Metabolic Phenotype ◽  
E Coli ◽  
Scale Models ◽  
Protein Components ◽  
K 12 ◽  
Genome Scale ◽  
Prosthetic Groups

AbstractSustaining a robust metabolic network requires a balanced and fully functioning proteome. In addition to amino acids, many enzymes require cofactors (coenzymes and engrafted prosthetic groups) to function properly. Extensively validated genome-scale models of metabolism and gene expression (ME-models) have the unique ability to compute an optimal proteome composition underlying a metabolic phenotype, including the provision of all required cofactors. Here we use the ME-model for Escherichia coli K-12 MG1655 to computationally examine how environmental conditions change the proteome and its accompanying cofactor usage. We found that: (1) The cofactor requirements computed by the ME model mostly agree with the standard biomass objective function used in models of metabolism alone (M models); (2) ME-model computations reveal non-intuitive variability in cofactor use under different growth conditions; (3) An analysis of ME-model predicted protein use in aerobic and anaerobic conditions suggests an enrichment in the use of prebiotic amino acids in the proteins used to sustain anaerobic growth (4) The ME-model could describe how limitation in key protein components affect the metabolic state of E. coli. Genome-scale models have thus reached a level of sophistication where they reveal intricate properties of functional proteomes and how they support different E. coli lifestyles.

scholarly journals The Anaerobic Regulatory Network Required for Pseudomonas aeruginosa Nitrate Respiration

2007 ◽  
Vol 189 (11) ◽  
pp. 4310-4314 ◽  
Author(s):  
Kerstin Schreiber ◽  
Robert Krieger ◽  
Beatrice Benkert ◽  
Martin Eschbach ◽  
Hiroyuki Arai ◽  
...  
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Dna Bending ◽  
Regulatory Gene ◽  
Regulatory System ◽  
Growth Conditions ◽  
Anaerobic Growth ◽  
Nitrate Respiration ◽  
Genetic Response ◽  
Anaerobic Conditions ◽  
Regulatory Model

ABSTRACT In Pseudomonas aeruginosa, the narK 1 K 2 GHJI operon encodes two nitrate/nitrite transporters and the dissimilatory nitrate reductase. The narK 1 promoter is anaerobically induced in the presence of nitrate by the dual activity of the oxygen regulator Anr and the N-oxide regulator Dnr in cooperation with the nitrate-responsive two-component regulatory system NarXL. The DNA bending protein IHF is essential for this process. Similarly, narXL gene transcription is enhanced under anaerobic conditions by Anr and Dnr. Furthermore, Anr and NarXL induce expression of the N-oxide regulator gene dnr. Finally, NarXL in cooperation with Dnr is required for anaerobic nitrite reductase regulatory gene nirQ transcription. A cascade regulatory model for the fine-tuned genetic response of P. aeruginosa to anaerobic growth conditions in the presence of nitrate was deduced.

Staphylococcal ClpXP protease targets the cellular antioxidant system to eliminate fitness-compromised cells in stationary phase

2021 ◽  
Vol 118 (47) ◽  
pp. e2109671118
Author(s):  
Abdulelah A. Alqarzaee ◽  
Sujata S. Chaudhari ◽  
Mohammad Mazharul Islam ◽  
Vikas Kumar ◽  
Matthew C. Zimmerman ◽  
...  
Keyword(s):  
Cell Death ◽  
Stationary Phase ◽  
Growth Conditions ◽  
Significant Loss ◽  
Protein Damage ◽  
Bacterial Populations ◽  
Competitive Fitness ◽  
Functional Conservation ◽  
Domains Of Life ◽  
Expression And Activity

The transition from growth to stationary phase is a natural response of bacteria to starvation and stress. When stress is alleviated and more favorable growth conditions return, bacteria resume proliferation without a significant loss in fitness. Although specific adaptations that enhance the persistence and survival of bacteria in stationary phase have been identified, mechanisms that help maintain the competitive fitness potential of nondividing bacterial populations have remained obscure. Here, we demonstrate that staphylococci that enter stationary phase following growth in media supplemented with excess glucose, undergo regulated cell death to maintain the competitive fitness potential of the population. Upon a decrease in extracellular pH, the acetate generated as a byproduct of glucose metabolism induces cytoplasmic acidification and extensive protein damage in nondividing cells. Although cell death ensues, it does not occur as a passive consequence of protein damage. Instead, we demonstrate that the expression and activity of the ClpXP protease is induced, resulting in the degeneration of cellular antioxidant capacity and, ultimately, cell death. Under these conditions, inactivation of either clpX or clpP resulted in the extended survival of unfit cells in stationary phase, but at the cost of maintaining population fitness. Finally, we show that cell death from antibiotics that interfere with bacterial protein synthesis can also be partly ascribed to the corresponding increase in clpP expression and activity. The functional conservation of ClpP in eukaryotes and bacteria suggests that ClpP-dependent cell death and fitness maintenance may be a widespread phenomenon in these domains of life.

scholarly journals Identification and Characterization ofMAE1, the Saccharomyces cerevisiae Structural Gene Encoding Mitochondrial Malic Enzyme

1998 ◽  
Vol 180 (11) ◽  
pp. 2875-2882 ◽  
Author(s):  
Eckhard Boles ◽  
Patricia de Jong-Gubbels ◽  
Jack T. Pronk
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Enzyme Activity ◽  
Pyruvate Kinase ◽  
Malic Enzyme ◽  
Fold Increase ◽  
Growth Conditions ◽  
Anaerobic Growth ◽  
Oxidative Decarboxylation ◽  
Mrna Levels ◽  
Malic Enzyme Activity

ABSTRACT Pyruvate, a precursor for several amino acids, can be synthesized from phosphoenolpyruvate by pyruvate kinase. Nevertheless, pyk1 pyk2 mutants of Saccharomyces cerevisiae devoid of pyruvate kinase activity grew normally on ethanol in defined media, indicating the presence of an alternative route for pyruvate synthesis. A candidate for this role is malic enzyme, which catalyzes the oxidative decarboxylation of malate to pyruvate. Disruption of open reading frame YKL029c, which is homologous to malic enzyme genes from other organisms, abolished malic enzyme activity in extracts of glucose-grown cells. Conversely, overexpression ofYKL029c/MAE1 from the MET25 promoter resulted in an up to 33-fold increase of malic enzyme activity. Growth studies with mutants demonstrated that presence of either Pyk1p or Mae1p is required for growth on ethanol. Mutants lacking both enzymes could be rescued by addition of alanine or pyruvate to ethanol cultures. Disruption of MAE1 alone did not result in a clear phenotype. Regulation of MAE1 was studied by determining enzyme activities and MAE1 mRNA levels in wild-type cultures and by measuring β-galactosidase activities in a strain carrying a MAE1::lacZ fusion. Both in shake flask cultures and in carbon-limited chemostat cultures,MAE1 was constitutively expressed. A three- to fourfold induction was observed during anaerobic growth on glucose. Subcellular fractionation experiments indicated that malic enzyme in S. cerevisiae is a mitochondrial enzyme. Its regulation and localization suggest a role in the provision of intramitochondrial NADPH or pyruvate under anaerobic growth conditions. However, since null mutants could still grow anaerobically, this function is apparently not essential.

scholarly journals Glutathionylspermidine metabolism in Escherichia coli

1995 ◽  
Vol 312 (2) ◽  
pp. 465-469 ◽  
Author(s):  
K Smith ◽  
A Borges ◽  
M R Ariyanayagam ◽  
A H Fairlamb
Keyword(s):  
Escherichia Coli ◽  
Glutathione Reductase ◽  
Growth Conditions ◽  
Anaerobic Growth ◽  
Growth Phases ◽  
Total Glutathione ◽  
Apparent Lack ◽  
E Coli ◽  
Catalytic Constant ◽  
Glutathione Disulphide

Intracellular levels of glutathione and glutathionylspermidine conjugates have been measured throughout the growth phases of Escherichia coli. Glutathionylspermidine was present in mid-log-phase cells, and under stationary and anaerobic growth conditions accounted for 80% of the total glutathione content. N1,N8-bis(glutathionyl)spermidine (trypanothione) was undetectable under all growth conditions. The catalytic constant kcat/Km of recombinant E. coli glutathione reductase for glutathionylspermidine disulphide was approx. 11,000-fold lower than that for glutathione disulphide. The much higher catalytic constant for the mixed disulphide of glutathione and glutathionylspermidine (11% that of GSSG), suggests a possible explanation for the low turnover of trypanothione disulphide by E. coli glutathione reductase, given the apparent lack of a specific glutathionylspermidine disulphide reductase in E. coli.

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