REDUCTION OF CYTOCHROME o

Gonzales-Prevatt, Victoria; Webster, D. R.

doi:10.1016/b978-0-12-164380-5.50027-x

Cited by 6 publications

(6 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Indeed, the peak (419 nm) and trough (430.5 nm) render the spectrum much more similar to that of oxidases of the cytochrome oЈ-type (peak at 415 nm, trough at 432 nm) (50,51) than to Vgb (peak at 419 nm, trough at 437 nm) (50). The closeness of the trough position to 427 nm and the blue-shifted band of the CO adduct suggest some low spin character (48), but the ␣/␤ regions are insufficiently resolved in spectra of crude extracts for further discussion on this point. Nevertheless, the growth data in Fig.…”

Section: Discussionmentioning

confidence: 88%

“…Interestingly, single domain hemoglobins such as Mycobacterium tuberculosis HbN (47) and Vgb from Vitreoscilla have also been implicated in NO detoxification processes (15,27). It has been suggested that, because Vgb interacts with a reductase from Vitreoscilla (48), this globin may function in a manner similar to flavohemoglobins. The NADHcytochrome o reductase has been shown to constitute an electron-transferring path for the oxidation of NADH and to increase the oxygen uptake severalfold in Vitreoscilla (21,28 ferring electrons to the globin heme, allowing turnover and ligand chemistry.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Flavohemoglobin Hmp, but Not Its Individual Domains, Confers Protection from Respiratory Inhibition by Nitric Oxide in Escherichia coli

Hernández-Urzúa¹,

Mills

White

et al. 2003

Journal of Biological Chemistry

View full text Add to dashboard Cite

Escherichia coli possesses a two-domain flavohemoglobin, Hmp, implicated in nitric oxide (NO) detoxification. To determine the contribution of each domain of Hmp toward NO detoxification, we genetically engineered the Hmp protein and separately expressed the heme (HD) and the flavin (FD) domains in a defined hmp mutant. Expression of each domain was confirmed by Western blot analysis. CO-difference spectra showed that the HD of Hmp can bind CO, but the CO adduct showed a slightly blue-shifted peak. Overexpression of the HD resulted in an improvement of growth to a similar extent to that observed with the Vitreoscilla hemeonly globin Vgb, whereas the FD alone did not improve growth. Viability of the hmp mutant in the presence of lethal concentrations of sodium nitroprusside was increased (to 30% survival after 2 h in 5 mM sodium nitroprusside) by overexpressing Vgb or the HD. However, maximal protection was provided only by holo-Hmp (75% survival under the same conditions). Cellular respiration of the hmp mutant was instantaneously inhibited in the presence of 13.5 M NO but remained insensitive to NO inhibition when these cells overexpressed Hmp. When HD or FD was expressed separately, no significant protection was observed. By contrast, overexpression of Vgb provided partial protection from NO respiratory inhibition. Our results suggest that, despite the homology between the HD from Hmp and Vgb (45% identity), their roles seem to be quite distinct.

show abstract

Section: Discussionmentioning

confidence: 88%

Section: Discussionmentioning

confidence: 99%

Flavohemoglobin Hmp, but Not Its Individual Domains, Confers Protection from Respiratory Inhibition by Nitric Oxide in Escherichia coli

Hernández-Urzúa¹,

Mills

White

et al. 2003

Journal of Biological Chemistry

View full text Add to dashboard Cite

show abstract

“…A soluble flavoprotein, NADH-Vitreoscilla Hb reductase, reduces the dimeric ferric protein when supplied with additional co factors (50).…”

Section: Chemical Reactivitymentioning

confidence: 99%

Mechanisms of Cytoplasmic Hemoglobin and Myoglobin Function

Wittenberg¹,

Wittenberg²

1990

Annu. Rev. Biophys. Biophys. Chem.

167

111

View full text Add to dashboard Cite

“…Stable reaction intermediates in bacterial cytochrome oxidases are not unprecedented, however. In the well-characterized cytochrome o of the aerobic myxobacterium Vitreoscilla, at least two intermediates have been observed (for a review, see Gonzales-Prevatt & Webster, 1979). Compound D may be trapped at 0°C and has features expected of an oxycompound.…”

Section: Hypo Thesismentioning

confidence: 99%

The 650 nm Chromophore in Escherichia coli is an 'Oxy-' or Oxygenated Compound, Not the Oxidized Form of Cytochrome Oxidase d: An Hypothesis

et al. 1983

View full text Add to dashboard Cite

The form of cytochrome d in Escherichia coli and Azotobacter vinelandii that shows an absorption maximum at 648 to 652 nm ('cytochrome d650') is generally regarded as the oxidized form of this terminal oxidase. Membranes from E. coli grown under oxygen-limited conditions, when treated with ferricyanide, do not reveal cytochrome d650, whereas a sharp symmetrical band at 652 nm results from the reaction of the reduced enzyme with O2 at either room temperature or after flash photolysis of the CO-liganded form at -130 degrees C. Electron paramagnetic resonance spectroscopy of cytochrome d650 trapped at -130 degrees C shows that its spectrum is indistinguishable from the CO-liganded form and does not reveal resonances of high spin ferric haem previously attributed to cytochrome d. An hypothesis is proposed in which cytochrome d650 is an early intermediate in the reaction of reduced cytochrome d650 and oxyhaemoglobin is presented and the hypothesis discussed in relation to earlier work, in which the indirect interconversions of reduced cytochrome d and d650 have been explained by proposing the existence of an 'invisible' form. It is suggested that this form could be the oxidized enzyme.

show abstract

REDUCTION OF CYTOCHROME o

Cited by 6 publications

References 26 publications

Flavohemoglobin Hmp, but Not Its Individual Domains, Confers Protection from Respiratory Inhibition by Nitric Oxide in Escherichia coli

Flavohemoglobin Hmp, but Not Its Individual Domains, Confers Protection from Respiratory Inhibition by Nitric Oxide in Escherichia coli

Mechanisms of Cytoplasmic Hemoglobin and Myoglobin Function

The 650 nm Chromophore in Escherichia coli is an 'Oxy-' or Oxygenated Compound, Not the Oxidized Form of Cytochrome Oxidase d: An Hypothesis

Contact Info

Product

Resources

About