Membrane-bound cytochrome c is an alternative electron donor for cytochrome aa3 in Nitrobacter winogradskyi

Nomoto, Toshi; Fukumori, Yoshihiro; Yamanaka, T.

doi:10.1128/jb.175.14.4400-4404.1993

Cited by 14 publications

(9 citation statements)

References 15 publications

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“…Similar membraneassociated C-type cytochromes have recently been described in some bacteria such as CycMin Bradyrhizobium japonicum (Bott et al, 1991), thecssl in Chlorobiumvibrioforme(Okke1s et al, 1992, and the c5500f Bacillussubtilis (von Wachenfeldt & Hederstedt, 1993). A newly reported membrane-associated C-type cytochrome in Nitrobacter winogradskyi may also be similar to cyt cy based on its proposed function and membrane location (Nomoto et al, 1993). Thus, membrane-associated electron carriers such as cyt cy may be more widely spread and may play a larger role in electron transport chains than has previously been suspected.…”

Section: Discussionmentioning

confidence: 90%

Roles of the Soluble Cytochrome c2 and Membrane-Associated Cytochrome cy of Rhodobacter capsulatus in Photosynthetic Electron Transfer

Jenney¹,

Prince²,

Daldal³

1994

Biochemistry

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Genetic evidence indicates that Rhodobacter capsulatus has two different pathways for reduction of the photooxidized reaction center (RC) [Jenney, F. E., & Daldal, F. (1993) EMBO J. 12, 1283-1292]. One pathway is via the water soluble cytochrome (cyt) c2, and the other is via a novel, membrane-associated c-type cytochrome, cyt cy, now believed to be identical to the cyt cx of Jones et al. [Jones, M. R., et al. (1990) Biochim. Biophys. Acta 975, 59-66] and c354 of Zannoni et al. [Zannoni, D., et al. (1992) Arch. Microbiol. 157, 367-374]. Mutants lacking either cyt c2, cyt cy, or the bc1 complex, as well as various combinations, were utilized to probe the functional role of these cytochromes in electron transfer. Data obtained by monitoring flas induced electron transfer kinetics in the RC, cyt c pool, cyt b, and the carotenoid band shift indicate that there are two pathways for electron transfer from the bc1 complex to the RC in R. capsulatus, one via cyt c2 and the other through cty cy. The two pathways show strikingly different kinetics for RC reduction and cyt c oxidation, and both are present in the wild-type strain MT-1131. After genetic inactivation of both cyt c2 and cyt cy there remains no flash oxidizible c-type cytochrome, and inactivation of cyt cy rather than cyt c2 has a more pronounced effect on the extent of the light-induced membrane potential under the conditions tested.(ABSTRACT TRUNCATED AT 250 WORDS)

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Section: Discussionmentioning

confidence: 90%

Roles of the Soluble Cytochrome c2 and Membrane-Associated Cytochrome cy of Rhodobacter capsulatus in Photosynthetic Electron Transfer

Jenney¹,

Prince²,

Daldal³

1994

Biochemistry

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“…DNA hybridization to coxA, coxB, and coxC probes revealed multiple copies of the cytochrome oxidase operon (11). Both soluble and membrane-bound class IA/B cytochrome c-550 proteins were purified and shown to be electron donors for Cox (67,87,102). Among the c-type cytochrome genes identified, orthologs for both cytochrome c-550 proteins (c-550s, nwi2582, and c-550m, nwi0712) were located.…”

Section: Resultsmentioning

confidence: 99%

Genome Sequence of the Chemolithoautotrophic Nitrite-Oxidizing Bacterium Nitrobacter winogradskyi Nb-255

Starkenburg

Chain

Sayavedra-Soto

et al. 2006

Appl Environ Microbiol

160

134

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The alphaproteobacterium Nitrobacter winogradskyi (ATCC 25391) is a gram-negative facultative chemolithoautotroph capable of extracting energy from the oxidation of nitrite to nitrate. Sequencing and analysis of its genome revealed a single circular chromosome of 3,402,093 bp encoding 3,143 predicted proteins. There were extensive similarities to genes in two alphaproteobacteria, Bradyrhizobium japonicum USDA110 (1,300 genes) and Rhodopseudomonas palustris CGA009 CG (815 genes). Genes encoding pathways for known modes of chemolithotrophic and chemoorganotrophic growth were identified. Genes encoding multiple enzymes involved in anapleurotic reactions centered on C 2 to C 4 metabolism, including a glyoxylate bypass, were annotated. The inability of N. winogradskyi to grow on C 6 molecules is consistent with the genome sequence, which lacks genes for complete Embden-Meyerhof and Entner-Doudoroff pathways, and active uptake of sugars. Two gene copies of the nitrite oxidoreductase, type I ribulose-1,5-bisphosphate carboxylase/oxygenase, cytochrome c oxidase, and gene homologs encoding an aerobictype carbon monoxide dehydrogenase were present. Similarity of nitrite oxidoreductases to respiratory nitrate reductases was confirmed. Approximately 10% of the N. winogradskyi genome codes for genes involved in transport and secretion, including the presence of transporters for various organic-nitrogen molecules. The N. winogradskyi genome provides new insight into the phylogenetic identity and physiological capabilities of nitrite-oxidizing bacteria. The genome will serve as a model to study the cellular and molecular processes that control nitrite oxidation and its interaction with other nitrogen-cycling processes.Nitrification, the microbiological process by which ammonia is converted to nitrate, is a major component of the global nitrogen cycle, plays a crucial role in transformation of fertilizer nitrogen in agricultural systems, and is a key component of nitrogen removal in wastewater treatment. Excess production of soluble nitrogen by nitrification results in the contamination of potable water and eutrophication of aquatic and terrestrial ecosystems, while the gaseous by-products of nitrification, nitric oxide and nitrous oxide, are two of the most potent greenhouse gases. As anthropogenic inputs of fixed nitrogen continue to expand to meet the demands of a growing global population, intimate knowledge of the nitrification process and the microorganisms that control this process will be necessary to address environmental nitrogen imbalances.Nitrobacter winogradskyi Nb-255 and other nitrite-oxidizing bacteria participate in nitrification by converting nitrite, the end product of ammonia oxidation, into nitrate according to the reaction NO 2 Ϫ ϩ H 2 O 3 NO 3 Ϫ ϩ 2H ϩ ϩ 2e Ϫ . Nitrite functions as an electron donor for the reduction of NAD via reverse electron flow and the generation of ATP by oxidative phosphorylation (36).As a facultative chemolithoautotroph, N. winogradskyi gains energy from nitrite oxidation, and fix...

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“…They are known for their heterotrophy (Bock 1976), mixotrophy (Smith & Hoare 1968), heterogeneity among species (Navarro et al 1992), anaerobic growth by dissimilatory nitrate reduction (Freitag et al 1987, Bock et al 1988. Freitag & Bock 1990, as well as alternate respiratory chains (Bock et al 1986, Nomoto et al 1993. The inherent metabolic diversity of nitrite oxidizers may be the key to their phototolerance.…”

Section: Discussionmentioning

confidence: 99%

Photoinhibition of marine nitrifying bacteria. I. Wavelength-dependent response

Ma¹,

Rd²

1996

Mar. Ecol. Prog. Ser.

156

111

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Axenic cultures of chemolithotrophic nitrifying bacteria (NH, ' and NOz-oxidizers) respond to light in distinct manners. After short-term (2 to 4 h ) monochromatic irradiations both types of nitrifying bacteria demonstrated a widespread photosensitivity in the near-UV region (300 to 375 nm) and a differential photosensitivity in the blue region of the spectrum (400 to 475 nm). Nitrite oxidizers were less sensitive overall to blue llght inhibition than were ammonium oxidizers. Character~stically, the extent of the photoinhibition was species-specific and light response was dose-and wavelength-dependent. Photoprotection by higher substrate concentrations was only observed with ammonium oxidizers. Increased cell densities altered the phototolerance of nitrite oxidizers and made these organisms light-susceptible. Similarly, treatment wlth a low light dose for extended periods was more damaging to nitrite oxidizers, when high cell densities were used. Polychromatic irradiations served to confirm the monochromatic results. Cool-white fluorescent light inhibited NH,' oxidizing activity but not NO2-oxidizing activity. Exposure to sunlight resulted in inhibition of activity in both types of nitrif~e r s .These data demonstrate that the effect of light on autotrophic nitrification depends not only on the type of nitrifier (NH,' or N O 2 oxidizer), but also on the conditions of their environment.

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Membrane-bound cytochrome c is an alternative electron donor for cytochrome aa3 in Nitrobacter winogradskyi

Cited by 14 publications

References 15 publications

Roles of the Soluble Cytochrome c2 and Membrane-Associated Cytochrome cy of Rhodobacter capsulatus in Photosynthetic Electron Transfer

Roles of the Soluble Cytochrome c2 and Membrane-Associated Cytochrome cy of Rhodobacter capsulatus in Photosynthetic Electron Transfer

Genome Sequence of the Chemolithoautotrophic Nitrite-Oxidizing Bacterium Nitrobacter winogradskyi Nb-255

Photoinhibition of marine nitrifying bacteria. I. Wavelength-dependent response

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