Nutrition and carbon metabolism of Methanococcus voltae

Whitman, William B.; Ankwanda, E; Wolfe, R. S.

doi:10.1128/jb.149.3.852-863.1982

Cited by 260 publications

(100 citation statements)

References 40 publications

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“…Similarly, IPMS activity was not detected in cell-free extract of the mutant S52 (<0.08 nmol mg À1 min À1 ), while the specific activity in the wild-type strain was 1.6 ± 0.3 nmol mg À1 min À1 . Isovalerate also fulfilled the leucine requirement for growth of S52 (not shown), suggesting that isovalerate is converted to leucine by volatile fatty acid ferredoxin oxidoreductase (VOR), as previously proposed for Methanococcus voltae [17]. These results confirm the identity of ORF Mmp1063 as leuA and its role in leucine biosynthesis.…”

Section: Construction Of a Leucine-auxotrophic Mutantsupporting

confidence: 84%

Continuous culture of under defined nutrient conditions

Haydock¹,

Porat²,

Whitman³

et al. 2004

FEMS Microbiology Letters

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To study global regulation in the methanogenic archaeon Methanococcus maripaludis, we devised a system for steady-state growth in chemostats. New Brunswick Bioflo 110 bioreactors were equipped with controlled delivery of hydrogen, nitrogen, carbon dioxide, hydrogen sulfide, and anaerobic medium. We determined conditions and media compositions for growth with three different limiting nutrients, hydrogen, phosphate, and leucine. To investigate leucine limitation we constructed and characterized a mutant in the leuA gene for 2-isopropylmalate synthase, demonstrating for the first time the function of this gene in the Archaea. Steady state specific growth rates in these studies ranged from 0.042 to 0.24 h(-1). Plots of culture density vs. growth rate for each condition showed the behavior predicted by growth modeling. The results show that growth behavior is normal and reproducible and validate the use of the chemostat system for metabolic and global regulation studies in M. maripaludis.

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Section: Construction Of a Leucine-auxotrophic Mutantsupporting

confidence: 84%

Continuous culture of under defined nutrient conditions

Haydock¹,

Porat²,

Whitman³

et al. 2004

FEMS Microbiology Letters

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“…1). Similar requirement and tolerance has been reported for M. t, oltae isolated from estuary [17]. Methanobacterium brvantii and…”

Section: Resultssupporting

confidence: 83%

Isolation of methanogens from Arabian sea sediments and their salt tolerance

Kadam¹,

Godbole²,

Ranade³

1989

FEMS Microbiology Letters

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Sea sediments in tropical regions have been less studied for methanogenesis and methanogens present therein. Three species of methanogens viz. Methanobacterium bryantii, Methanococcus voltae and Methanosarcina barkeri were isolated from Arabian sea sediments collected near the west coast of India. Maximum methane was formed by M. voltae at 3.0% (w/v) NaCl and other two methanogens at 0.06% (w/v) NaCl. M. bryantii and M. barkeri tolerated 2.5 and 3.0% (w/v) NaCl respectively due to which these methanogens must have survived in salt conditions of the sea sediments.

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“…M. voltue PS (DSM 1537) was grown at 37°C in 10 1 batch cultures with a HJCO, (80:20) gas phase. The growth medium described by Whitman et al [35] was used with the following modifications. Cysteine and sodium sulfide were omitted.…”

Section: Methodsmentioning

confidence: 99%

Changes in the Electronic Structure Around Ni in Oxidized and Reduced Selenium‐Containing Hydrogenases from Methanococcus Voltae

Sorgenfrei

Duin

Klein

et al. 1997

European Journal of Biochemistry

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The selenium-containing F420-reducing hydrogenase from Methanococcus voltae was anaerobically purified to a specific hydrogen-uptake activity of 350 U/mg protein as determined with the natural electron acceptor. The concentrated enzyme was used for EPR-spectroscopic investigations. As isolated, the enzyme showed an EPR spectrum with gnyL values of 2.21, 2.15 and 2.01. Illumination of such samples at low temperatures led to an EPR spectrum with gxyz values of 2.05, 2.11 and 2.29. These spectra are typical for [NiFeIhydrogenases in the active state. Spectra of samples enriched in 77Se showed a hyperfine interaction between the unpaired spin of the nickel ion and the nuclear spin of one "Se atom before and after illumination. A 90" flip of the electronic z-axis is proposed to explain the hyperfine interaction in both states. This has been demonstrated previously only for the F420-non-reducing hydrogenase from M . voltue, where the selenium atom is present as a selenocysteine residue on an unusuallyThe results demonstrate that the three-dimensional structures of the active sites in the selenium-containing F420-reducing and F420-non-reducing hydrogenases from M. voltue are highly similar and hence are not influenced by the unusual subunit structure of the latter enzyme. Oxidized samples containing either natural selenium or 77Se were prepared from the F420-reducing and the selenium-containing F420-nonreducing hydrogenase. Both enzymes exhibited EPR spectra typical for [NiFeIhydrogenases in the inactive 'ready' state. In contrast to the reduced form, no splitting of the nickel-derived signal due to the nuclear spin of "Se was observed in the oxidized state, indicating that the electronic z-axis is perpendicular to the Ni-Se direction.Keywords: [NiFeIhydrogenase ; EPR ; purification ; selenium ; selenocysteine.The simplest biochemical redox reaction, namely the reversible, heterolytic cleavage of dihydrogen into two protons and two electrons is catalysed by enzymes called hydrogenases [I, 21. These are found in many organisms from all three domains, bacteria, eukarya and archaea. Different classes are defined according to the metal content of the enzymes. One class comprises hydrogenases containing no metal other than iron. These enzymes are called Fe-only hydrogenases or [Felhydrogenases [l]. The second class consists of hydrogenases that contain nickel in addition to iron. Accordingly these enzymes were named [NiFeIhydrogenases. Most of the characterized hydrogenases belong to this group. The EPR spectra of nickel respond to redox changes [4-71 and this M. voltae is an anaerobic archaeon that gains energy by oxidation of hydrogen via hydrogenases and concomitant reduction Correspondence to 0. Sorgenfrei,

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Nutrition and carbon metabolism of Methanococcus voltae

Cited by 260 publications

References 40 publications

Continuous culture of under defined nutrient conditions

Continuous culture of under defined nutrient conditions

Isolation of methanogens from Arabian sea sediments and their salt tolerance

Changes in the Electronic Structure Around Ni in Oxidized and Reduced Selenium‐Containing Hydrogenases from Methanococcus Voltae

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