Hemerythrin: Further studies of Mössbauer spectra

Garbett, K.; Johnson, C. E.; Klotz, Irving M.; Okamura, M. Y.; Williams, R. J. P.

doi:10.1016/0003-9861(71)90521-2

Cited by 46 publications

(39 citation statements)

References 13 publications

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“…All of these representations would be consistent with our magnetic susceptibility data and also with the difference in Mossbauer quadrupole splittings (1.0 and 1.9 mm per sec) for the two iron atoms found by previous workers (Okamura et al, 1969;York and Bearden, 1970;Garbett et at., 1971).…”

Section: I11supporting

confidence: 93%

“…Mossbauer measurements (Okamura et a/., 1969;York and Bearden, 1970;Garbett et al, 1971) have been used to show that the iron atoms in deoxyhemerythrin exist as high-spin iron(I1) (ie., SI = Sz = 2). The decrease in the paramagnetic contribution to the room-temperature susceptibility on comparison of deoxy-t o oxy-or methemerythrin (Kubo, 1953;Okamura et al, 1969;York and Bearden, 1970) could be due to antiferromagnetic interaction between pairs of high-or low-spin iron(II1) atoms or t o the formation of species containing isolated low-spin iron(II1) atoms.…”

Section: Discussionmentioning

confidence: 99%

“…coil vibrating sample magnetometer could not resolve changes in susceptibility with temperature for oxy-and several methemerythrins (Moss e f al., 1971). Consequently, Mossbauer spectroscopy has been a more valuable technique for confirming the presence (but not the magnitude) of magnetic interaction between the iron atoms in oxy-and methemerythrin (Okamura et al, 1969;Garbett et a/., 1971).…”

mentioning

confidence: 99%

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Magnetic susceptibility study of hemerythrin using an ultrasensitive magnetometer

Dawson¹,

Gray²,

Hoenig³

et al. 1972

Biochemistry

124

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Section: I11supporting

confidence: 93%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Magnetic susceptibility study of hemerythrin using an ultrasensitive magnetometer

Dawson¹,

Gray²,

Hoenig³

et al. 1972

Biochemistry

124

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“…Fe3+ doublets of equal intensities. This indicates that the reoxidation of monooxygenase disturbs the equivalence of two iron sites in the active centre, probably due to asymmetric spacing of the dioxygen binding site relative to the ferric atoms in the cluster, as it is assumed for hemerythrine (Garbett et at., 1971;Clark and Webb, 1981).…”

Section: Mossbauer-spectroscopy Characteristicsmentioning

confidence: 94%

“…In this case an exchange interaction between spins of the neighbouring ferric irons provides fast spin relaxation and the absence of a hf pattern in the spectra. It is observed, for example, for (2Fe-2s) iron-sulfur proteins (Rao et al, 1971;Dunham et at., 1971;Johnson, 1986;Miinck et al, 1972;Fee et al, 1984), hemerythrin (Garbett et al, 1971;Clark and Webb, 1981) and the hydroxylase of methane monooxygenase from Methylosinus trichosporium (Fox et al, 1988), where active centres contain iron clusters, formed by a pair of high-spin Fe3+ ions. In addition note that the Mossbauer spectra of the native monooxygenase are qualitatively similar to those of the native hydroxylase (Fox et al, 1988).…”

Section: Mossbauer-spectroscopy Characteristicsmentioning

confidence: 95%

Investigation of the Quaternary Structure and of the Active Site of Methane Monooxygenase from Methane-Oxidizing Bacteria Methylococcus capsulatus (strain M) by Physico-Chemical Methods

et al. 1990

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Methane monooxygenase (MMO, E.C. 1.14.13.25) was purified from membranes of the methaneoxidizing bacterium Methylococcus capsulatus (strain M) and separated into two components: monooxygenase and NADH-oxidoreductase. The individual components did not oxidize methane. Oxidation of the substrate was observed in the presence of two components. MMO specific activity was 3600 nmol CH,/min/mg of the protein. The degree of purification was 170. The criterion of purity was sodium dodecyl sulfate-polyacrylamide gel electrophoresis, which showed that the monooxygenase and NADH-reductase consist of subunits with a molecular weight of 35 f 3 kDa and 45 f 3 kDa, respectively. From gel chromatography on Sephadex G-200, a molecular weight of 180 kDa was found for the native NADH-reductase, suggesting a tetrameric structure for this enzyme. The quaternary structure of the NADH-reductase and monooxygenase were investigated by electron microscopy. NADH-reductase is constructed from four identical subunits with molecular weight of about 45 kDa.Two-dimensional crystalline arrays of the monooxygenase have been obtained. The monooxygenase has an hexagonal arrangement of the subunits. This enzyme contains 2 atom iron per mol of protein.One mol of FAD and 2 atoms of iron were found in one mol of NADH-reductase. The visible absorption spectrum of NADH-reductase exhibits maxima at 270, 395 and 465 nm. The apparent K,,, values of the NADH-reductase for NADH and NADPH were calculated from Lineweaver-Burk plots as 3 and 50 p~, respectively, V , , = 7.0 . M/s. NADH-reductase reduces several redox compounds: 2.6-dichlorophenolindophenol, nitroblue tetrazolium, neotetrazolium, iodonitrotetrazolium and ferricyanide.Mossbauer studies of the native monooxygenase show the presence of two near high-spin ferric ions.KEY WORDS Methane monooxygenase, NADH-reductase, enzyme structure, electron microscopy, methane-oxidizing bacteria, active site of enzyme. 39Biocatal Biotransformation Downloaded from informahealthcare.com by McMaster University on 02/06/15 For personal use only. Biocatal Biotransformation Downloaded from informahealthcare.com by McMaster University on 02/06/15 For personal use only. Biocatal Biotransformation Downloaded from informahealthcare.com by McMaster University on 02/06/15 For personal use only.

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Hemerythrin

Stenkamp¹

2004

Handbook of Metalloproteins

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Hemerythrin is a non‐heme iron protein that serves as an oxygen transfer or storage protein in several marine invertebrate phyla (sipunculids, brachiopods, priapulids and annelids). Each protein subunit (13 500 kD) binds two iron atoms by histidine, aspartic acid, and glutamic acid side‐chains. The protein carboxylates and a μ‐oxygen atom bridge the iron atoms in a prototypic FeOFe complex that has been extensively studied. One iron binds exogenous ligands including dioxygen and small anions. The protein functions by reversibly adding dioxygen to a deoxy form containing ferrous iron to produce an oxy form containing ferric iron and a peroxo anion.

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Hemerythrin: Further studies of Mössbauer spectra

Cited by 46 publications

References 13 publications

Magnetic susceptibility study of hemerythrin using an ultrasensitive magnetometer

Magnetic susceptibility study of hemerythrin using an ultrasensitive magnetometer

Investigation of the Quaternary Structure and of the Active Site of Methane Monooxygenase from Methane-Oxidizing Bacteria Methylococcus capsulatus (strain M) by Physico-Chemical Methods

Hemerythrin

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