1887

Abstract

The soluble flavohaemoglobin (Hmp) of , product of the gene, contains haem B and FAD in a single polypeptide of molecular mass 44 kDa. The function of this protein (and of the similar proteins identified in several bacteria and yeast) is unknown, but the observation that the binding of oxygen to haem modulates the reduction level of FAD has suggested that Hmp could act as an oxygen sensor. Here, stopped-flow, rapid-scan spectroscopy has shown that the oxidized protein reacts rapidly with NADH to form an oxygenated species, even when efforts are made to reduce oxygen concentrations to sub-micromolar levels, suggesting a high affinity for this ligand. As is the case at high oxygen concentrations (130 μM), oxygenated species formation was kinetically and spectrally heterogeneous. Between 12 ms and 1 s after mixing, following transient formation of the deoxy form and its reaction with dioxygen, a steady-state level of the oxygenated species was attained. During the oxygenated steady state, the flavin remained largely oxidized, as observed previously at 130 μM oxygen. Hmp is an NADH oxidase; on exhaustion of oxygen by reduction (in < 10 s under these conditions), the oxygenated species disappeared to generate the deoxy Fe(II) haem, whereupon the flavin was reduced. The affinity for oxygen during NADH oxidation was measured by continuous dual-wavelength monitoring of the deoxygenation of oxymyoglobin. The for oxygen was 2.6 μM, much higher than the values determined, using the same method, for the membrane-bound terminal oxidases cytochromes and . These results show that the oxidase activity of Hmp, but not necessarily oxygen binding, would be minimal at oxygen concentrations that limit terminal oxidase function.

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1996-05-01
2024-05-01
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References

  1. Andrews S.C., Shipley D., Keen J.N., Findlay J.B.C., Harrison P.M., Guest J.R. The haemoglobin-like protein (HMP) of Escherichia coli has ferrisiderophore reductase activity and its C-terminal shares homology with ferredoxin NADP+ reductases. FEBS Lett 1992; 302:247–252
    [Google Scholar]
  2. Appleby C.A., Bergersen F.J. Preparation and experimental use of leghaemoglobin. In Methods of Evaluating Biological Nitrogen Fixation 1980 Edited by Bergersen F.J. Chichester: John Wiley; pp 315–335
    [Google Scholar]
  3. Boerman S., Webster D.A. Control of heme content in Vitreoscilla by oxygen. J Gen Appl Microbiol 1982; 28:35–43
    [Google Scholar]
  4. Chance B., Legallais V., Sorge J., Graham N. A versatile time-sharing multichannel spectrophotometer, reflectometer, and fluorometer. Anal Biochem 1975; 66:498–514
    [Google Scholar]
  5. Cooper C.E., Ioannidis N., D'mello R., Poole R.K. Haem, flavin and oxygen interactions in Hmp, a flavohaemoglobin from Escherichia coli. Biochem Soc Trans 1994; 22:709–713
    [Google Scholar]
  6. Cotter P.A., Chepuri V., Gennis R.B., Gunsalus R.P. Cytochrome o (cyoABCDE) and d (cydAB) oxidase gene expression in Escherichia coli is regulated by oxygen, pH, and the fnr gene product. J Bacteriol 1990; 172:6333–6338
    [Google Scholar]
  7. Cramm R., Siddiqui R.A., Friedrich B. Primary sequence and evidence for a physiological function of the flavohaemoprotein of Alcaligenes eutrophus. J Biol Chem 1994; 269:7349–7354
    [Google Scholar]
  8. D'mello R., Hill S., Poole R.K. Determination of the oxygen affinities of terminal oxidases in Azotobacter vinelandii using the deoxygenation of oxyleghaemoglobin and oxymyoglobin: cytochrome bdis a low-affinity oxidase. Microbiology 1994; 140:1395–1402
    [Google Scholar]
  9. D'mello R., Hill S., Poole R.K. The oxygen affinity of cytochrome bo' in Escherichia coli determined by the deoxygenation of oxyleghemoglobin and oxymyoglobin; Km values for oxygen are in the submicromolar range. J Bacteriol 1995; 111:867–870
    [Google Scholar]
  10. D'mello R., Hill S., Poole R.K. The cytochrome bd quinol oxidase in Escherichia coli has an extremely high oxygen affinity and two oxygen-binding haems: implications for regulation of activity in vivo by oxygen inhibition. Microbiology 1996; 142 (in press)
    [Google Scholar]
  11. Eschenbrenner M., Coves J., Fontecave M. Ferric reductases in Escherichia coli: the contribution of the haemoglobinlike protein. Biochem Biophys Res Commun 1994; 198:127–131
    [Google Scholar]
  12. Favey S., Labesse G., Vouille V., Boceara M. Flavo-haemoglobin HmpX: a new pathogenicity determinant in Erwinia chrysanthemi strain 3937. Microbiology 1995; 141:863–871
    [Google Scholar]
  13. Gilles-González M.A., González G., Perutz M.F. Kinase activity of oxygen sensor FixL depends on the spin state of its heme iron. Biochemistry 1995; 34:232–236
    [Google Scholar]
  14. Hidalgo E., Demple B. An iron-sulfur center essential for transcriptional activation by the redox-sensing SoxR protein. EMBO J 1994; 13:138–146
    [Google Scholar]
  15. Loannidis N., , Cooper C.E., Poole R.K. Spectroscopic studies on an oxygen-binding haemoglobin-like flavohaemoprotein from Escherichia coli. Biochem J 1992; 288:649–655
    [Google Scholar]
  16. Iwaasa H., Takagi T., Shikama K. Amino acid sequence of yeast hemoglobin. A two-domain structure. J Mol Biol 1992; 227:948–954
    [Google Scholar]
  17. Jones C.W. Aerobic respiratory systems in bacteria. In Microbial Energetics 1977 Edited by Haddock B.A., Hamilton W.A. Cambridge: Cambridge University Press; pp 23–59
    [Google Scholar]
  18. Karplus P.A., Bruns C.M. Structure-function relation for ferredoxin reductase. J Bioenerg Biomembr 1994; 26:89–99
    [Google Scholar]
  19. Khoroshilova N., Beinert H., Kiley P.J. Association of a polynuclear iron-sulfur center with a mutant FNR protein enhances DNA binding. Proc Natl Acad Sci USA 1995; 92:2499–2503
    [Google Scholar]
  20. Khosla C., Bailey J.E. Heterologous expression of a bacterial haemoglobin improves the growth properties of recombinant Escherichia coli. Nature 1988; 331:633–635
    [Google Scholar]
  21. Khosravi M., Webster D.A., Stark B.C. Presence of the bacterial hemoglobin gene improves a-amylase production of a recombinant Escherichia coli strain. Plasmid 1990; 24:190–194
    [Google Scholar]
  22. Orii Y. Immediate reduction of cytochrome c by photoexcited NADH: reaction mechanism as revealed by flow-flash and rapid-scan studies. Biochemistry 1993; 32:11910–11914
    [Google Scholar]
  23. Orii Y., Webster D.A. Photodissociation of oxygenated cytochrome o(s) (Vitreoscilla) and kinetic studies of reassociation. J Biol Chem 1986; 261:3544–3547
    [Google Scholar]
  24. Orii Y., Loannidis N., Poole R.K. The oxygenated flavohaemoglobin from Escherichia coli: evidence from photodissociation and rapid-scan studies for two kinetic and spectral forms. Biochem Biophys Res Commun 1992; 187:94–100
    [Google Scholar]
  25. Oshino R., Oshino N., Chance B., Hagihara B. Studies on yeast hemoglobin. The properties of yeast hemoglobin and its physiological function in the cell. Eur J Biochem 1973a; 35:23–33
    [Google Scholar]
  26. Oshino R., Asakura T., Tajio K., Oshino N., Chance B., Hagihara B. Purification and molecular properties of yeast hemoglobin. Eur J Biochem 1973b; 39:581–590
    [Google Scholar]
  27. Perutz M.F. A bacterial haemoglobin. Nature 1986; 322:405
    [Google Scholar]
  28. Poole R.K. Oxygen reactions with bacterial oxidases and globins: binding, reduction and regulation. Antonie Leeuwenhoek 1994; 65:289–310
    [Google Scholar]
  29. Poole R.K., Chance B. Oxidase names: to ‘ 3 ’ or not to ‘3’. Microbiology 1995; 141:752–753
    [Google Scholar]
  30. Poole R.K., Loannidis N., Orii Y. Reactions of the Escherichia coli flavohaemoglobin (Hmp) with oxygen and reduced nicotinamide adenine dinucleotide: evidence for oxygen switching of flavin oxidoreduction and a mechanism for oxygen sensing. Proc R Soc Eond B 1994; 255:251–258
    [Google Scholar]
  31. Potts M., Angeloni S.V., Ebel R.E., Bassam D. Myoglobin in a cyanobacterium. Science 1992; 256:1690–1692
    [Google Scholar]
  32. Probst I., Wolf G., Schlegel H.G. An oxygen-binding flavohemoprotein from Alcaligenes eutrophus. Biochim Biophys Acta 1979; 576:471–478
    [Google Scholar]
  33. Rice C.W., Hempfling W.P. Oxygen-limited continuous culture and respiratory energy conservation in Escherichia coli. J Bacteriol 1978; 134:115–124
    [Google Scholar]
  34. Takagi T. Hemoglobins from single-celled organisms. Curr Opin Struct Biol 1993; 3:413–418
    [Google Scholar]
  35. Unden G., Becker S., Bongaerts J., Holighaus G., Schirawski J., Six S. Oa-sensing and 02-dependent gene regulation in facultatively anaerobic bacteria. Arch Microbiol 1995; 164:81–90
    [Google Scholar]
  36. Vasudevan S.G., Armarego W.L.F., Shaw D.C., Lilley P.E., Poole R.K. Isolation and nucleotide sequence of the hmp gene that encodes a haemoglobin-like protein in Escherichia coli K-12. Mol Gen Genet 1991; 226:49–58
    [Google Scholar]
  37. Vasudevan S.G., Tang P., Dixon N.E., Poole R.K. Distribution of the flavohaemoglobin, HMP, between periplasm and cytoplasm in Escherichia coli. FEMS Microbiol Lett 1995; 125:219–224
    [Google Scholar]
  38. Wakabayashi S., Matsubara H., Webster D.A. Primary sequence of a dimeric haemoglobin from Vitreoscilla. Nature 1986; 322:481–483
    [Google Scholar]
  39. Webster D.A. Structure and function of bacterial hemoglobin and related proteins. In Advances in Inorganic Chemistry 1987 Edited by Eichhorn G.L., Marzilli L.G. New York: Elsevier; 7 pp 245–265
    [Google Scholar]
  40. Webster D.A., Liu C.Y. Reduced nicotinamide adenine dinucleotide cytochrome o reductase associated with cytochrome o purified from Vitreoscilla. J Biol Chem 1974; 249:4257–4260
    [Google Scholar]
  41. Wood P.M. Bacterial proteins with CO-binding b- or c-type haem. Functions and absorption spectroscopy. Biochim Biophys Acta 1984; 768:293–317
    [Google Scholar]
  42. Zhu H., Riggs A.F. Yeast flavohemoglobin is an ancient protein related to globins and a reductase family. Proc Natl Acad Sci USA 1992; 89:5015–5019
    [Google Scholar]
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