scholarly journals The oxidation of nicotinic acid by Pseudomonas ovalis Chester. The terminal oxidase

1972 ◽  
Vol 129 (3) ◽  
pp. 755-761 ◽  
Author(s):  
M. V. Jones ◽  
D. E. Hughes
Keyword(s):  
Electron Transport ◽  
Nicotinic Acid ◽  
Electron Transport Chain ◽  
Acid Oxidase ◽  
Terminal Oxidase ◽  
Difference Spectra ◽  
Terminal Oxidases ◽  
Cytochrome O ◽  
Transport Chain ◽  
Terminal Oxidation

In cell-free extracts of Pseudomonas ovalis nicotinic acid oxidase is confined to the wallmembrane fraction. It is associated with an electron-transport chain comprising b- and c-type cytochromes only, differing proportions of which are reduced by nicotinate and NADH. CO difference-spectra show two CO-binding pigments, cytochrome o (absorption maximum at 417nm) and another component absorbing maximally at 425nm. Cytochrome o is not reduced by NADH or by succinate but is by nicotinate, which can also reduce the ‘425’ CO-binding pigment. The effects of inhibitors of terminal oxidation support the idea of two terminal oxidases and a scheme involving the ‘425’ CO-binding pigment and the other components of the electron-transport chain is proposed.

scholarly journals Terminal Respiratory Oxidases: A Targetables Vulnerability of Mycobacterial Bioenergetics?

2020 ◽  
Vol 10 ◽  
Author(s):  
Sapna Bajeli ◽  
Navin Baid ◽  
Manjot Kaur ◽  
Ganesh P. Pawar ◽  
Vinod D. Chaudhari ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electron Transport ◽  
Molecular Oxygen ◽  
Electron Transport Chain ◽  
Drug Targets ◽  
Atp Synthesis ◽  
Terminal Oxidase ◽  
Terminal Oxidases ◽  
Transport Chain ◽  
Synthase Inhibitor

Recently, ATP synthase inhibitor Bedaquiline was approved for the treatment of multi-drug resistant tuberculosis emphasizing the importance of oxidative phosphorylation for the survival of mycobacteria. ATP synthesis is primarily dependent on the generation of proton motive force through the electron transport chain in mycobacteria. The mycobacterial electron transport chain utilizes two terminal oxidases for the reduction of oxygen, namely the bc1-aa3 supercomplex and the cytochrome bd oxidase. The bc1-aa3 supercomplex is an energy-efficient terminal oxidase that pumps out four vectoral protons, besides consuming four scalar protons during the transfer of electrons from menaquinone to molecular oxygen. In the past few years, several inhibitors of bc1-aa3 supercomplex have been developed, out of which, Q203 belonging to the class of imidazopyridine, has moved to clinical trials. Recently, the crystal structure of the mycobacterial cytochrome bc1-aa3 supercomplex was solved, providing details of the route of transfer of electrons from menaquinone to molecular oxygen. Besides providing insights into the molecular functioning, crystal structure is aiding in the targeted drug development. On the other hand, the second respiratory terminal oxidase of the mycobacterial respiratory chain, cytochrome bd oxidase, does not pump out the vectoral protons and is energetically less efficient. However, it can detoxify the reactive oxygen species and facilitate mycobacterial survival during a multitude of stresses. Quinolone derivatives (CK-2-63) and quinone derivative (Aurachin D) inhibit cytochrome bd oxidase. Notably, ablation of both the two terminal oxidases simultaneously through genetic methods or pharmacological inhibition leads to the rapid death of the mycobacterial cells. Thus, terminal oxidases have emerged as important drug targets. In this review, we have described the current understanding of the functioning of these two oxidases, their physiological relevance to mycobacteria, and their inhibitors. Besides these, we also describe the alternative terminal complexes that are used by mycobacteria to maintain energized membrane during hypoxia and anaerobic conditions.

scholarly journals Induction of Terminal Oxidases of Electron Transport Chain in Broccoli Heads under Controlled Atmosphere Storage

Foods ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 380 ◽  
Author(s):  
Yoshio Makino ◽  
Jun Inoue ◽  
Hsiao-Wen Wang ◽  
Masatoshi Yoshimura ◽  
Kensaku Maejima ◽  
...  
Keyword(s):  
Electron Transport ◽  
Mass Loss ◽  
Electron Transport Chain ◽  
Biological Properties ◽  
Controlled Atmosphere ◽  
High Co2 ◽  
Terminal Oxidases ◽  
Transport Chain ◽  
Atmosphere Storage ◽  
Oxygen Isotope Discrimination

Controlled atmosphere (CA) storage, that is, at low O2 and high CO2 concentrations, effectively extends the shelf life of horticultural products. The influence of CA storage (O2/CO2: 2.5%/6.0% or 2.5%/0.0%) and in normal air (both at 1 °C for 21 d) on the physicochemical (O2 uptake, mass loss and L-ascorbate) and biological properties of broccoli (Brassica oleracea var. italica, Plenck, 1794) via amounts and activities of terminal oxidases of the electron transport chain was investigated. Mass loss, a sensitive index of freshness for broccoli heads under CA, was significantly lower under CA than under normoxia (p < 0.05). Mass loss was depressed 7 d earlier under CA, including 6.0% CO2 than under CA without CO2. High CO2 effectively depressed the degradation of L-ascorbate. During storage, the activity of the alternative oxidase (AOX) was lower under CA than in normal air (p < 0.05), while the amount of cytochrome c oxidase (COX), and the AOX/COX activity ratio (based on oxygen isotope discrimination), were not affected during storage. Our results indicate that CA storage effectively retained the freshness of broccoli heads by depressing the induction of AOX. However, depression of AOX amount was not associated with CO2 around broccoli heads.

scholarly journals CtaM Is Required for Menaquinol Oxidaseaa3Function inStaphylococcus aureus

mBio ◽  
2016 ◽  
Vol 7 (4) ◽  
Author(s):  
Neal D. Hammer ◽  
Lici A. Schurig-Briccio ◽  
Svetlana Y. Gerdes ◽  
Robert B. Gennis ◽  
Eric P. Skaar
Keyword(s):  
Staphylococcus Aureus ◽  
Electron Transport ◽  
Electron Transport Chain ◽  
Molecular Mechanisms ◽  
Carbon Sources ◽  
Spectroscopic Studies ◽  
Uncharacterized Protein ◽  
Terminal Oxidases ◽  
Transport Chain ◽  
Genes Encoding

ABSTRACTStaphylococcus aureusis the leading cause of skin and soft tissue infections, bacteremia, osteomyelitis, and endocarditis in the developed world. The ability ofS. aureusto cause substantial disease in distinct host environments is supported by a flexible metabolism that allows this pathogen to overcome challenges unique to each host organ. One feature of staphylococcal metabolic flexibility is a branched aerobic respiratory chain composed of multiple terminal oxidases. Whereas previous biochemical and spectroscopic studies reported the presence of three different respiratory oxygen reductases (otype,bdtype, andaa3type), the genome contains genes encoding only two respiratory oxygen reductases,cydABandqoxABCD. Previous investigation showed thatcydABandqoxABCDare required to colonize specific host organs, the murine heart and liver, respectively. This work seeks to clarify the relationship between the genetic studies showing the unique roles of thecydABandqoxABCDin virulence and the respiratory reductases reported in the literature. We establish that QoxABCD is anaa3-type menaquinol oxidase but that this enzyme is promiscuous in that it can assemble as abo3-type menaquinol oxidase. However, thebo3form of QoxABCD restricts the carbon sources that can support the growth ofS. aureus. In addition, QoxABCD function is supported by a previously uncharacterized protein, which we have named CtaM, that is conserved in aerobically respiringFirmicutes. In total, these studies establish the heme A biosynthesis pathway inS. aureus, determine that QoxABCD is a typeaa3menaquinol oxidase, and reveal CtaM as a new protein required for typeaa3menaquinol oxidase function in multiple bacterial genera.IMPORTANCEStaphylococcus aureusrelies upon the function of two terminal oxidases, CydAB and QoxABCD, to aerobically respire and colonize distinct host tissues. Previous biochemical studies support the conclusion that a third terminal oxidase is also present. We establish the components of theS. aureuselectron transport chain by determining the heme cofactors that interact with QoxABCD. This insight explains previous observations by revealing that QoxABCD can utilize different heme cofactors and confirms that the electron transport chain ofS. aureusis comprised of two terminal menaquinol oxidases. In addition, a newly identified protein, CtaM, is found to be required for the function of QoxABCD. These results provide a more complete assessment of the molecular mechanisms that support staphylococcal respiration.

scholarly journals RESPIRATION AND PROTEIN SYNTHESIS IN ESCHERICHIA COLI MEMBRANE-ENVELOPE FRAGMENTS

1970 ◽  
Vol 46 (1) ◽  
pp. 114-129 ◽  
Author(s):  
Richard W. Hendler ◽  
N. Nanninga
Keyword(s):  
Escherichia Coli ◽  
Carbon Monoxide ◽  
Electron Transport ◽  
Electron Transport Chain ◽  
Wave Length ◽  
Spectrophotometric Analysis ◽  
Difference Spectra ◽  
Absorption Bands ◽  
Optical Extinction ◽  
Transport Chain

The membranous nature of pellets obtained from broken Escherichia coli spheroplasts by successive centrifugation at 3500 g (P1), 20,000 g (P2), and 105,000 g (P3), has been established by electron microscopy. Spectrophotometric analysis has shown that about 90% of the cytochromes are concentrated in the particulate fractions. The crude ribosomal pellet (P3) contained as much of the total cytochromes as did the pellet obtained at 20,000 g (P2). The high cytochrome content of P3 is consistent with its high oxidative activity (1) and the presence of membrane vesicles in this fraction. Analysis at 77°K intensified the optical extinction of all the cytochrome absorption bands, but the degree of intensification was not uniform for each fraction nor for each band within a given fraction. Carbon monoxide had little or no inhibiting effect on NADH oxidation. Reduced plus carbon monoxide difference spectra yielded artifactual absorption bands in the wave length regions where reduced vs. oxidized absorption bands normally occur. Succinate and NADH, either together or separately, reduced nearly all of the cytochromes, indicating that the cytochrome portion of the electron-transport chain is shared by both substrates. A tentative formulation of the electron-transport chain is presented.

Occurrence of P503 in microorganisms

1973 ◽  
Vol 19 (10) ◽  
pp. 1235-1238
Author(s):  
Andrew M. B. Kropinski ◽  
Joyce Boon ◽  
Rozanne Poulson ◽  
W. James Polglase
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Electron Transport ◽  
Functional Significance ◽  
Electron Transport Chain ◽  
Difference Spectra ◽  
Widespread Occurrence ◽  
Facultative Anaerobes ◽  
Transport Chain ◽  
Apparent Correlation ◽  
The Difference

A pigment absorbing at 503 nm (P503) was observed in the difference spectra of several strains of microorganisms. The pigment was present in most facultative anaerobes and absent from many but not all of the aerobes examined. P503 is probably not a component of the normal oxygen-linked electron transport chain since the pigment was present in both respiratory sufficient (ρ+) and deficient (ρ−) strains of Saccharomyces cerevisiae. There was no apparent correlation between P503 and either the cytochromes or any known metabolic cellular activities. However, the widespread occurrence of P503 in microorganisms suggests that it is of functional significance.

Induction and Activity of Terminal Oxidases of Electron Transport Chain in Broccoli Heads under Controlled Atmosphere Storage

2019 ◽  
Author(s):  
Yoshio Makino ◽  
Jun Inoue ◽  
Hsiao-Wen Wang ◽  
Masatoshi Yoshimura ◽  
Kensaku Maejima ◽  
...  
Keyword(s):  
Electron Transport ◽  
Mass Loss ◽  
Electron Transport Chain ◽  
Biological Properties ◽  
Controlled Atmosphere ◽  
Terminal Oxidases ◽  
Transport Chain ◽  
Horticultural Products ◽  
Atmosphere Storage ◽  
Oxygen Isotope Discrimination

Controlled atmosphere (CA) storage, under atmospheres with low O2 and high CO2 concentrations, is effective for extending the shelflife of horticultural products. We investigated the influence of CA storage (O2/CO2: 2.5%/6.0% or 2.5%/0.0%) at 1C for 21 d versus normoxia (normal air) on the physicochemical and biological properties of broccoli (Brassica oleracea var. italica, Plenck, 1794) via amounts and activities of terminal oxidases of electron transport chain. Mass loss, a sensitive index of freshness for broccoli heads under CA, was significantly lower under CA than under normoxia. The effect for depressing mass loss was observed 7 d earlier under CA including 6.0% CO2 than under CA without CO2. Environmental CO2 was also effective for depressing loss of L-ascorbate. The alternative oxidase (AOX) level under CA was lower than under normoxia during storage, while the level of cytochrome c oxidase (COX), and the AOX/COX activity ratio (based on oxygen isotope discrimination), were stable during storage. Our results indicate that CA storage is effective for retaining freshness of broccoli heads during storage by depressing the induction of AOX. However, depression of AOX level was found to be independent of environmental CO2.

scholarly journals Impact of Molecular Hydrogen on Chalcopyrite Bioleaching by the Extremely Thermoacidophilic Archaeon Metallosphaera sedula

2010 ◽  
Vol 76 (8) ◽  
pp. 2668-2672 ◽  
Author(s):  
Kathryne S. Auernik ◽  
Robert M. Kelly
Keyword(s):  
Energy Source ◽  
Electron Transport ◽  
Molecular Hydrogen ◽  
Electron Transport Chain ◽  
Open Reading Frames ◽  
Terminal Oxidase ◽  
Metallosphaera Sedula ◽  
Transport Chain ◽  
Heterotrophic Metabolism ◽  
Reading Frames

ABSTRACT Hydrogen served as a competitive inorganic energy source, impacting the CuFeS 2 bioleaching efficiency of the extremely thermoacidophilic archaeon Metallosphaera sedula. Open reading frames encoding key terminal oxidase and electron transport chain components were triggered by CuFeS2. Evidence of heterotrophic metabolism was noted after extended periods of bioleaching, presumably related to cell lysis.

The electron transport chain of Bacterionema matruchotii

1981 ◽  
Vol 27 (10) ◽  
pp. 1106-1113
Author(s):  
Murray F. Broom ◽  
Maxwell G. Shepherd ◽  
Patrick A. Sullivan
Keyword(s):  
Electron Transport ◽  
Membrane Fraction ◽  
Electron Transport Chain ◽  
Uv Light ◽  
Reductase Activity ◽  
Light Irradiation ◽  
Cytochrome O ◽  
Uv Light Irradiation ◽  
Transport Chain ◽  
Inhibition Studies

The membrane fraction of Bacterionema matruchotii contains an electron transport chain with oxidizing activity for NADH and succinate. Respiration was inhibited by KCN, 2-heptyl-4-hydroxyquinoline-N-oxide, UV light irradiation and CO. UV light irradiation, analysis of membrane extracts, and reconstitution of respiration in UV light treated membranes suggested that respiration is mediated by a menaquinone derivative. The membranes contained cytochromes a, b, and c. Inhibition studies and the effect of KCN and CO on the cytochrome spectrum indicated the presence of an a + a3 cytochrome oxidase and cytochrome o. The membrane fraction from cells grown under O2-limiting conditions contained nitrate reductase activity. In B. matruchotii, electron transport is coupled to oxidative phosphorylation as judged by the effects of substrates and inhibitors on the intracellular ATP concentration.

Sign in / Sign up

Export Citation Format

Share Document