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Pathways of autotrophic CO2 fixation and of dissimilatory nitrate reduction to N2O in Ferroglobus placidus

Pathways of autotrophic CO2 fixation and of dissimilatory nitrate reduction to N2O in Ferroglobus... The strictly anaerobic Archaeon Ferroglobus placidus was grown chemolithoautotrophically on H 2 and nitrate and analyzed for enzymes and coenzymes possibly involved in autotrophic CO 2 fixation. The following enzymes were found (values in parentheses = μmol min –1 (mg protein) –1 ): formylmethanofuran dehydrogenase (0.2), formylmethanofuran:tetrahydromethanopterin formyltransferase (0.6), methenyltetrahydromethanopterin cyclohydrolase (10), F 420 -dependent methylenetetrahydromethanopterin dehydrogenase (1.5), F 420 -dependent methylenetetrahydromethanopterin reductase (0.4), and carbon monoxide dehydrogenase (0.1). The cells contained coenzyme F 420 (0.4 nmol/mg protein), tetrahydromethanopterin (0.9 nmol/ mg protein), and cytochrome b (4 nmol/mg membrane protein). From the enzyme and coenzyme composition of the cells, we deduced that autotrophic CO 2 fixation in F. placidus proceeds via the carbon monoxide dehydrogenase pathway as in autotrophically growing Archaeoglobus and Methanoarchaea species. Evidence is also presented that cell extracts of F. placidus catalyze the reduction of two molecules of nitrite to 1 N 2 O with NO as intermediate (0.1 μmol N 2 O formed per min and mg protein), showing that – at least in principle – F. placidus has a denitrifying capacity. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Archives of Microbiology Springer Journals

Pathways of autotrophic CO2 fixation and of dissimilatory nitrate reduction to N2O in Ferroglobus placidus

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References (30)

Publisher
Springer Journals
Copyright
Copyright © 1997 by Springer-Verlag Berlin Heidelberg
Subject
Legacy
ISSN
0302-8933
eISSN
1432-072X
DOI
10.1007/s002030050411
Publisher site
See Article on Publisher Site

Abstract

The strictly anaerobic Archaeon Ferroglobus placidus was grown chemolithoautotrophically on H 2 and nitrate and analyzed for enzymes and coenzymes possibly involved in autotrophic CO 2 fixation. The following enzymes were found (values in parentheses = μmol min –1 (mg protein) –1 ): formylmethanofuran dehydrogenase (0.2), formylmethanofuran:tetrahydromethanopterin formyltransferase (0.6), methenyltetrahydromethanopterin cyclohydrolase (10), F 420 -dependent methylenetetrahydromethanopterin dehydrogenase (1.5), F 420 -dependent methylenetetrahydromethanopterin reductase (0.4), and carbon monoxide dehydrogenase (0.1). The cells contained coenzyme F 420 (0.4 nmol/mg protein), tetrahydromethanopterin (0.9 nmol/ mg protein), and cytochrome b (4 nmol/mg membrane protein). From the enzyme and coenzyme composition of the cells, we deduced that autotrophic CO 2 fixation in F. placidus proceeds via the carbon monoxide dehydrogenase pathway as in autotrophically growing Archaeoglobus and Methanoarchaea species. Evidence is also presented that cell extracts of F. placidus catalyze the reduction of two molecules of nitrite to 1 N 2 O with NO as intermediate (0.1 μmol N 2 O formed per min and mg protein), showing that – at least in principle – F. placidus has a denitrifying capacity.

Journal

Archives of Microbiology – Springer Journals

Published: Jan 1, 1997

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