The L‐form of <i>N</i>‐7‐mercaptoheptanoyl‐<i>O</i>‐phosphothreonine is the enantiomer active as component B in methyl‐CoM reduction to methane

Kobelt, André; Pfaltz, Andreas; Ankel‐Fuchs, Dorothe; Thauer, Rudolf K.

doi:10.1016/0014-5793(87)80067-4

Cited by 29 publications

(15 citation statements)

References 12 publications

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“…0-Phospho-DL-threonine, and 2-mercaptoethanesulfonic acid were from Sigma (Deisenhofen, FRG). 0-Phospho-L-threonine and 0-phospho-D-threonine were synthesized as in [33]. 7-Bromoheptanoic acid was from Riedel-de-Haen (Hannover, FRG), and 8-bromooctanoic acid from Aldrich (Steinheim, FRG).…”

Section: Methodsmentioning

confidence: 99%

“…1) [30 -321. The D-form of H-S-HTP was neither active nor inhibitory [33]. Evidence has been presented that H-S-HTP functions as an electron carrier rather than as a methyl group carrier in methyl-CoM reduction to methane [34, 351. In this communication we report that highly purified methyl-coenzyme M reductase from M .…”

Section: Component Bmentioning

confidence: 99%

“…With the D-enantiomer only 2% of the specific activity was observed and this can be explained by the 2-3% L-form present in the D-threonine used to synthesize this molecule [33]. The C8-carboxylic acid homologue of H-S-HTP (H-S-OcoTP) was completely inactive.…”

Section: Specificity Of Methyl-com Reductase For H-s-htp As Electron mentioning

confidence: 99%

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The final step in methane formation

Ellermann¹,

Hedderich²,

Böcher³

et al. 1988

European Journal of Biochemistry

242

145

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Methyl‐coenzyme M reductase (= component C) from Methanobacterium thermoautotrophicum (strain Marburg) was highly purified via anaerobic fast protein liquid chromatography on columns of Mono Q and Superose 6. The enzyme was found to catalyze the reduction of methylcoenzyme M (CH3‐S‐CoM) with N‐7‐mercaptoheptanoylthreonine phosphate (H‐S‐HTP = component B) to CH4. The mixed disulfide of H‐S‐CoM and H‐S‐HTP (CoM‐S‐S‐HTP) was the other major product formed. The specific activity was up to 75 nmol min−1 mg protein−1. In the presence of dithiothreitol and of reduced corrinoids or titanium(III) citrate the specific rate of CH3‐S‐CoM reduction to CH4 with H‐S‐HTP increased to 0.5–2 μmol min−1 mg protein−1. Under these conditions the CoM‐S‐S‐HTP formed from CH3‐S‐CoM and H‐S‐HTP was completely reduced to H‐S‐CoM and H‐S‐HTP. Methyl‐CoM reductase was specific for H‐S‐HTP as electron donor. Neither N‐6‐mercaptohexanoylthreonine phosphate (H‐S‐HxoTP) nor N‐8‐mercaptooctanoylthreonine phosphate (H‐S‐OcoTP) nor any other thiol compound could substitute for H‐S‐HTP. On the contrary, H‐S‐HxoTP (apparent Ki=0.1 μM) and H‐S‐OcoTP (apparent Ki= 15 μM) were found to be effectives inhibitors of methyl‐CoM reductase, inhibition being non‐competitive with CH3‐S‐CoM and competitive with H‐S‐HTP.

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Section: Methodsmentioning

confidence: 99%

Section: Component Bmentioning

confidence: 99%

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The final step in methane formation

Ellermann¹,

Hedderich²,

Böcher³

et al. 1988

European Journal of Biochemistry

242

145

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“…L-threonine Following the procedure of Noll et al [18], a solution of O-phospho-L-threonine [15] (546 mg, 2.74mmol) and triethylamine (0.76ml, 5.47 mmol) in 5 ml water was added to a solution of the N-hydroxysuccinimide ester (672 mg, 2.46 mmol) in 40 ml tetrahydrofuran. Addition of acetonitrile (14 ml) resulted in a homogeneous reaction mixture which was stirred at room temperature under argon for 36 h. After evaporation of the solvents (30°C, 10 -3 Torr) the residue was taken up in 25 ml of 1 M HCI and washed with dichloromethane (3 × 10ml).…”

Section: Methodsmentioning

confidence: 99%

“…1 mol coenzyme M (2-mercaptoethanesulfonate, HSCoM) [6,9,11] and an undefined amount of component B [12]. The structure of component B has recently been assigned as N-7-mercaptoheptanoyl-O-phospho-Lthreonine (7-mercaptoheptanoylthreonine phosphate, HSHTP) [13][14][15].…”

Section: Introductionmentioning

confidence: 99%

On the role of N‐7‐mercaptoheptanoyl‐O‐phospho‐L‐threonine (component B) in the enzymatic reduction of methyl‐coenzyme M to methane

Ellermann

Kobelt²,

Pfaltz³

et al. 1987

FEBS Letters

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The reduction of methyl-coenzyme M (CH3SCoM) to methane in methanogenic bacteria is dependent on component B (N-7-mercaptoheptanoyl-O-phospho-L-threonine, HSHTP). We report here that S-methylcomponent B (N-7-(methylthio)heptanoyl-O-phospho-L-threonine, CH3SHTP) can substitute for neither CH3SCoM nor HSHTP in the methyl-CoM reductase reaction. Rather, CH3SHTP proved to be an inhibitor competitive with HSHTP (apparent Ki = 6 gM) and noncompetitive with CH3SCoM. These results make it very unlikely that HSHTP functions as a methyl group carrier. A role for HSHTP as direct electron donor for CH3SCoM reduction to CH4 is proposed.

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Coenzyme F430 from Methanogenic Bacteria: Oxidation of F430 Pentamethyl Ester to the Ni(III) Form

Jaun¹

1990

Helvetica Chimica Acta

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~ ~~F430M, the pentamethyl ester of coenzyme F430, can be oxidized reversibly by one electron. The oxidation potential has been determined, and the electrolytically prepared oxidation product was characterized by its UVjVIS and ESR spectrum. The strongly anisotropic and nearly axial ESR spectrum is consistent with a S = ' / > species with the unpaired-electron spin density predominantly in a dZ2-type orbital of the central nickel ion. The properties of Ni(III)F430M are discussed in the context of two hypothetical mechanisms for the catalytic role of coenzyme F430 in methyl coenzyme M reductase, which catalyses the last step of methane formation in methanogenic bacteria. Introduction. -Factor F430 [l], the hydrocorphinoid nickel complex 1, is the prosthetic group of methyl coenzyme M reductase [2] which catalyses the last step of CH, formation in methanogenic bacteria according to Scheme 1 [3].While recent biophysical evidence points to a change of the redox state of coenzyme F430 during the catalytic cycle [5], the specific mechanism by which the enzyme catalyses this process is still unknown. One conceivable way of activation of the C-S bond in methyl coenzyme M is the addition of a thiyl radical to the thioether, followed by transfer of a Me group from the sulfuranyl intermediate to the Ni center of coenzyme F430.

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The L‐form of N‐7‐mercaptoheptanoyl‐O‐phosphothreonine is the enantiomer active as component B in methyl‐CoM reduction to methane

Cited by 29 publications

References 12 publications

The final step in methane formation

The final step in methane formation

On the role of N‐7‐mercaptoheptanoyl‐O‐phospho‐L‐threonine (component B) in the enzymatic reduction of methyl‐coenzyme M to methane

Coenzyme F430 from Methanogenic Bacteria: Oxidation of F430 Pentamethyl Ester to the Ni(III) Form

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