The interaction between methanol dehydrogenase and the autoreducible cytochromes <i>c</i> of the facultative methylotroph <i>Pseudomonas</i> AM1

O'Keeffe, David T.; Anthony, Christopher

doi:10.1042/bj1900481

Cited by 34 publications

(15 citation statements)

References 15 publications

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“…It was difficult to prepare samples at pH values higher than 8, due to an increase of cytochrome autoreduction as the pH increases. In agreement with the proposals of Tanaka et al [15] and O'Keeffe and Anthony [16], that a radical species is formed upon reduction of the heme iron, we observed in the EPR spectra of M. bruunii cytochrome c6 a radical signal at higher pH values, in some samples.…”

Section: Ferricytochrome Eprsupporting

confidence: 92%

“…This fact has been described for other hemeproteins, but its origin is still unknown [14-161. Tanaka et al [15] and O'Keeffe and Anthony [16] have proposed that a radical species is formed upon reduction of the heme iron. In agreement with this proposal, in the EPR spectra of M. bruunii cytochrome c,, a radical signal was observed at high pH values for some samples.…”

Section: Isolation and Purification Of Cytochrome C6mentioning

confidence: 99%

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Cytochrome c₆ from Monoraphidium braunii

Campos

Aguiar

Hervás

et al. 1993

European Journal of Biochemistry

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A soluble monoheme c-type cytochrome (cytochrome c,) has been isolated from the green alga Monoraphidium braunii. It has a molecular mass of 9.3 kDa, an isoelectric point of 3.6 and a reduction potential of 358 mV at pH 7. The determined amino acid sequence allows its classification as a class-I c-type cytochrome. The femc and ferrous cytochrome forms and their pH equilibria have been studied using 'H-NMR, ultraviolet/visible, EPR and Mossbauer spectroscopies. The pH equilibria are complex, several pK, values and pH-dependent forms being observed. The amino acid sequence, the reduction-potential value and the visible and NMR spectroscopies data in the pH range 4-9 indicate that the heme iron has a methionine-histidine axial coordination. However, the EPR and Mossbauer data obtained for the ferricytochrome show that in this pH range two distinct forms are present: form I, g, = 3.27, g, = 2.05 and g, = 1.05; form 11, g, = 2.95, g, = 2.29 and g, = 1.43. While form I has crystal-field parameters typical of a methionine-histidine coordination, those associated with form I1 would suggest a histidine-histidine axial ligation. This possibility was extensively analyzed by spectroscopic methods and by chemical modification of a histidine residue. It was concluded that form I1 actually corresponds to an unusual type of methionine-histidine axial coordination. Straightforward examples of this type of coordination have recently been found in other c-type hemeproteins [

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Section: Ferricytochrome Eprsupporting

confidence: 92%

Section: Isolation and Purification Of Cytochrome C6mentioning

confidence: 99%

Cytochrome c₆ from Monoraphidium braunii

Campos

Aguiar

Hervás

et al. 1993

European Journal of Biochemistry

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“…All methylotrophic bacteria contain at least two soluble cytochromes c, which are designated as cytochrome CL and cytochrome Cn according to their isoelectric point (O'Keeffe and Anthony 1980). These isoelectric points are 4.6 and 9.2, respectively, in the case of Methylophaga marina 42 (Janvier et al 1992).…”

Section: Introductionmentioning

confidence: 99%

Interaction of cytochrome c L with methanol dehydrogenase from Methylophaga marina 42:

et al. 1992

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The reaction of methanol dehydrogenase with cytochrome CL from Methylophaga marina and the reactions of the non-physiological substrates, Wurster's blue and ascorbic acid, with both proteins were studied as a function of temperature (4-32°C), pressure (1-2000 bar) and ionic strength using the optical high pressure stopped-flow method. The thermodynamic parameters AH*, AS+ + and AV* were determined for all reactions where electron transfers are involved. These data allowed the determination of the Maxwell relationships which proved the internal thermodynamic consistency of the system under study. A conformational change on the cytochrome CL level was deduced from both breaks in the Arrhenius plots and the variation of the AV++ with temperature.

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“…It is likely, therefore, that in whole cells of M . methylotrophus this cytochrome has at most only very slight oxidase activity; its ability to bind CO may reflect an interaction with methanol dehydrogenase [20] rather than with oxygen.…”

Section: Inhibition Of the Terminal Region Of The Respiratory Chain Bmentioning

confidence: 99%

Energy Conservation in the Terminal Region of the Respiratory Chain of the Methylotrophic Bacterium Methylophilus methylotrophus

Dawson

Jones

1981

European Journal of Biochemistry

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Reduced + C O minus reduced differencc spectra of respiratory membranes prepared from methanol-limited cultures of Methylophilus methylotrophus confirm the presence of three CO-binding cytochromes i.e. cytochromes nu3, o and cco. The kinetics of cyanide inhibition indicate that the respiratory chain of this organism is branched at the level of cytochrome c to two major terminal oxidases, viz. cytochromes uu3 and 0 ; cytochrome c, , , is probably not a physiologically significant oxidase. Determination of proton and charge translocation stoichionietries (+ H+/O and + Kf/O quotients) during oxidation of ascorbate-N,N, ","-tetramethylp-phenylenediamine shows that the terminal oxidase system of this organism exhibits a net inward translocation of 2e-, but no net proton translocation, when a pair of electrons are passed from cytochrome c to oxygen. The use of appropriate concentrations of cyanide to selectively inhibit cytochrome o indicates that the overall translocation stoichiometries are achieved by the two oxidases, ua3 and o, functioning similarly. These and other results suggest that methanol oxidase is organised as a simple redox arm with the methanol oxidation site and the oxygen consumption site(s) on thc periplasmic and cytoplasmic faces of the inner membrane respectively.Methylophilus methylotrophus is a niethylotrophic bacterium which is used by I.C.I. for single-cell protein production from methanol [I ]. This organism oxidises methanol via an NAD(P)+-independent methanol dehydrogenase [2] similar to the enzyme first described by Anthony and Zatman [3]. This enzyme is linked to a novel coenzyme which was originally thought to be a pteridine [4], but which has recently been shown to be a nitrogen-containing orthoquinone [5,6] and has been given the trivial names methoxatin [5] or pyrrolo-quinoline quinone [6].The respiratory system of M . methylotrophus contains three energy-conserving sites each of which translocates charges [7]. Only the third site is involved in the oxidation of methanol, which donates electrons to the respiratory chain at the level of cytochrome c [8,9]. This organism contains three species of cytochrome c which bind CO to varying degrees [lo], as do the cytochromes c of other methylotrophs [ l l , 121. Cytochrome c, , is not thought to act as a terminal oxidase in M . methylotrophus [9], but oxidase functions have been claimed for the cytochromes c,, of Methylosinus trichosporiuin [I31 and Beneckea nutriegens [14]. Due to the importance of the methanol oxidase reaction to the energy metabolism of this organism, and the potential complexity of the terminal region of the respiratory chain evidenced by the multiplicity of CO-binding cytochromes (i.e. cytochromes aa3, 0, cCO [9, 15]), a further investigation of this region of the respiratory chain was carried out.This paper describes the sensitivity of the terminal cytochrome system of M . methylotrophus to the classical inhibitor KCN, and the use of the artificial substrate ascorbate/ Ahhrcviarions. Ph (NMez)z, N,N,N',N'-tetrainethyl-...

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The interaction between methanol dehydrogenase and the autoreducible cytochromes c of the facultative methylotroph Pseudomonas AM1

Cited by 34 publications

References 15 publications

Cytochrome c₆ from Monoraphidium braunii

Cytochrome c₆ from Monoraphidium braunii

Interaction of cytochrome c L with methanol dehydrogenase from Methylophaga marina 42:

Energy Conservation in the Terminal Region of the Respiratory Chain of the Methylotrophic Bacterium Methylophilus methylotrophus

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The interaction between methanol dehydrogenase and the autoreducible cytochromes c of the facultative methylotroph Pseudomonas AM1

Cited by 34 publications

References 15 publications

Cytochrome c6 from Monoraphidium braunii

Cytochrome c6 from Monoraphidium braunii

Interaction of cytochrome c L with methanol dehydrogenase from Methylophaga marina 42:

Energy Conservation in the Terminal Region of the Respiratory Chain of the Methylotrophic Bacterium Methylophilus methylotrophus

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Product

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Cytochrome c₆ from Monoraphidium braunii

Cytochrome c₆ from Monoraphidium braunii