GLORIA

GEOMAR Library Ocean Research Information Access

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Studies on the biosynthesis of coenzyme F420 in methanogenic bacteria (1984)
    Springer
    Archives of microbiology 137 (1984), S. 362-365 
    Details
    ISSN: 1432-072X
    Keywords: Coenzyme F420 ; Flavin biosynthesis ; Deazaflavins ; Guanine assimilation ; Methanogenic bacteria ; Methanobacterium thermoautotrophicum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Coenzyme F420 is a 8-hydroxy-5-deazaflavin present in methanogenic bacteria. We have investigated whether the pyrimidine ring of the deazaflavin originates from guanine as in flavin biosynthesis, in which the pyrimidine ring of guanine is conserved. For this purpose the incorporation of [2-14C]guanine and of [8-14C]guanine into F420 by growing cultures of Methanobacterium thermoautotrophicum was studied. Only in the case of [2-14C]guanine did F420 become labeled. The specific radioactivity of the deazaflavin and of guanine isolated from nucleic acids of [2-14C]guanine grown cells were identical. This finding suggests that the pyrimidine ring of the deazaflavin and of flavins are synthesized by the same pathway. F420 did not become labeled when M. thermoautotrophicum was grown in the presence of methyl-[14C] methionine, [U-14C]phenylalanine or [U-14C]tyrosine. This excludes that C-5 of the deazaflavin is derived from the methyl group of methionine and that the benzene ring comes from phenylalanine or tyrosine.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00410735
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Enzymes and coenzymes of the carbon monoxide dehydrogenase pathway for autotrophic CO2 fixation in Archaeoglobus lithotrophicus and the lack of carbon monoxide dehydrogenase in the heterotrophic A. profundus (1995)
    Springer
    Archives of microbiology 163 (1995), S. 112-118 
    Details
    ISSN: 1432-072X
    Keywords: Methanofuran ; Tetrahydromethanopterin ; Coenzyme F420 ; Corrinoids ; Cytochromes ; Autotrophic CO2 fixation ; Dissimilatory sulfate reduction ; Archaeoglobus species ; Methanogenic Archaea
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Archaeoglobus lithotrophicus is a hyperthermophilic Archaeon that grows on H2 and sulfate as energy sources and CO2 as sole carbon source. The autotrophic sulfate reducer was shown to contain all the enzyme activities and coenzymes of the reductive carbon monoxide dehydrogenase pathway for autotrophic CO2 fixation as operative in methanogenic Archaea. With the exception of carbon monoxide dehydrogenase these enzymes and coenzymes were also found in A. profundus. This organism grows lithotrophically on H2 and sulfate, but differs from A. lithotrophicus in that it cannot grow autotrophically: A. profundus requires acetate and CO2 for biosynthesis. The absence of carbon monoxide dehydrogenase in A. profundus is substantiated by the observation that this organism, in contrast to A. lithotrophicus, is not mini-methanogenic and contains only relatively low concentrations of corrinoids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00381784
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    A F420-dependent NADP reductase in the extremely thermophilic sulfate-reducing Archaeoglobus fulgidus (1993)
    Springer
    Archives of microbiology 160 (1993), S. 199-205 
    Details
    ISSN: 1432-072X
    Keywords: Archaea ; Sulfate reducers ; Hyperthermophiles ; Coenzyme F420 ; Deazaflavin ; F420-dependent NADP reducatase ; Stereoselectivity ; Stereospecificity ; Archaeoglobus fulgidus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Archaeoglobus fulgidus, a sulfate-reducing Archaeon with a growth temperature optimum of 83°C, uses the 5-deazaflavin coenzyme F420 rather than pyridine nucleotides in catabolic redox processes. The organism does, however, require reduced pyridine nuclcotides for biosynthetic purposes. We describe here that the Archaeon contains a coenzyme F420-dependent NADP reductase which links anabolism to catabolism. The highly thermostable enzyme was purfied 3600-fold by affinity chromatography to apparent homogeneity in a 60% yield. The native enzyme with an apparent molecular mass of 55 kDa was composed of only one type of subunit of apparent molecular mass of 28 kDa. Spectroscopic analysis of the enzyme did not reveal the presence of any chromophoric prosthetic group. The purified enzyme catalyzed the reversible reduction of NADP (apparent K M 40 μM) with reduced F420 (apparent K M 20μM) with a specific activity of 660 U/mg (apparent V max) at pH 8.0 (pH optimum) and 80°C (temperature optimum). It was specific for both coenzyme F420 and NADP. Sterochemical investigations showed that the F420-dependent NADP reductase was Si face specific with respect to C5 of F420 and Si face specific with respect to C4 of NADP.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00249125
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Methyltetrahydromethanopterin as an intermediate in methanogenesis from acetate in Methanosarcina barkeri (1989)
    Springer
    Archives of microbiology 151 (1989), S. 459-465 
    Details
    ISSN: 1432-072X
    Keywords: Methanogenesis from acetate ; Methanopterin ; Methanofuran ; Coenzyme F420 ; Coenzyme M ; 7-Mercaptoheptanoylthreonine phosphate (=component B) ; Methanosarcina barkeri
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cell extracts (100,000×g) of acetate grown Methanosarcina barkeri (strain MS) catalyzed CH4 and CO2 formation from acetyl-CoA with specific activities of 50 nmol·min-1·mg protein-1. CH4 formation was found to be dependent on tetrahydromethanopterin (H4MPT) (apparent K M=4 μM), coenzyme M (H-S-CoM), and 7-mercaptoheptanoylthreonine phosphate (H-S-HTP=component B) rather than on methanofuran (MFR) and coenzyme F420 (F420). Methyl-H4MPT was identified as an intermediate. This compound accumulated when H-S-CoM and H-S-HTP were omitted from the assays. These and previous results indicate that methanogenesis from acetate proceeds via acetyl phosphate, acetyl-CoA, methyl-H4MPT, and CH3-S-CoM as intermediates. The disproportionation of formaldehyde to CO2 and CH4 was also studied. This reaction was shown to be dependent on H4MPT, MFR, F420, H-S-CoM, and H-S-HTP.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00416607
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Two N 5, N 10-methylenetetrahydromethanopterin dehydrogenases in the extreme thermophile Methanopyrus kandleri: characterization of the coenzyme F420-dependent enzyme (1993)
    Springer
    Archives of microbiology 160 (1993), S. 186-192 
    Details
    ISSN: 1432-072X
    Keywords: Coenzyme F420 ; Tetrahydromethanopterin ; Hydrogenase ; H2-forming methylenetrahydromethanopterin dehydrogenase ; Methanobacterium thermoautotrophicum ; Methanosarcina barkeri ; Archaeoglobus fulgidus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract It was recently reported that the extreme thermophile Methanopyrus kandleri contains only a H2-forming N 5, N 10-methylenetetrahydromethanopterin dehydrogenase which uses protons as electron acceptor. We describe here the presence in this Archaeon of a second N 5,N 10-methylenetetrahydromethanopterin dehydrogenase which is coenzyme F420-dependent. This enzyme was purified and characterized. The enzyme was colourless, had an apparent molecular mass of 300 kDa, an isoelectric point of 3.7±0.2 and was composed of only one type of subunit of apparent molecular mass of 36 kDa. The enzyme activity increased to an optimum with increasing salt concentrations. Optimal salt concentrations were e.g. 2 M (NH4)2SO4, 2 M Na2HPO4, 1.5 M K2HPO4, and 2 M NaCl. In the absence of salts the enzyme exhibited almost no activity. The salts affected mainly the V max rather than the K m of the enzyme. The catalytic mechanism of the dehydrogenase was determined to be of the ternary complex type, in agreement with the finding that the enzyme lacked a chromophoric prosthetic group. In the presence of M (NH4)2SO4 the V max was 4000 U/mg (k cat=2400 s-1) and the K m for N 5,N 10-methylenetetrahydromethanopterin and for coenzyme F420 were 80 μM and 20 μM, respectively. The enzyme was relatively heat-stable and lost no activity when incubated anaerobically in 50 mM K2HPO4 at 90°C for one hour. The N-terminal amino acid sequence was found to be similar to that of the F420-dependent N 5, N 10-methylenetetrahydromethanopterin dehydrogenase from Methanobacterium thermoautotrophicum, Methanosarcina barkeri, and Archaeoglobus fulgidus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00249123
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Pathways of autotrophic CO2 fixation and of dissimilatory nitrate reduction to N2O in Ferroglobus placidus (1997)
    Springer
    Archives of microbiology 167 (1997), S. 19-23 
    Details
    ISSN: 1432-072X
    Keywords: Key words Autotrophic CO2 fixation ; Dissimilatory ; nitrate reduction ; Archaeoglobus species ; Methanogenic Archaea ; Methanofuran ; Tetrahydromethanopterin ; Coenzyme F420 ; Cytochromes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The strictly anaerobic Archaeon Ferroglobus placidus was grown chemolithoautotrophically on H2 and nitrate and analyzed for enzymes and coenzymes possibly involved in autotrophic CO2 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), F420-dependent methylenetetrahydromethanopterin dehydrogenase (1.5), F420-dependent methylenetetrahydromethanopterin reductase (0.4), and carbon monoxide dehydrogenase (0.1). The cells contained coenzyme F420 (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 CO2 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 N2O with NO as intermediate (0.1 μmol N2O formed per min and mg protein), showing that – at least in principle –F. placidus has a denitrifying capacity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002030050411
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Activities of formylmethanofuran dehydrogenase, methylenetetrahydromethanopterin dehydrogenase, methylenetetrahydromethanopterin reductase, and heterodisulfide reductase in methanogenic bacteria (1991)
    Springer
    Archives of microbiology 155 (1991), S. 459-465 
    Details
    ISSN: 1432-072X
    Keywords: Methanogenic bacteria ; Methanofuran ; Coenzyme M ; Tetrahydromethanopterin ; Coenzyme F420 ; Disulfide reductase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The activities of formylmethanofuran dehydrogenase, methylenetetrahydromethanopterin dehydrogenase, methylenetetrahydromethanopterin reductase, and heterodisulfide reductase were tested in cell extracts of 10 different methanogenic bacteria grown on H2/CO2 or on other methanogenic substrates. The four activities were found in all the organisms investigated: Methanobacterium thermoautotrophicum,M. wolfei, Methanobrevibacter arboriphilus, Methanosphaera stadtmanae, Methanosarcina barkeri (strains Fusaro and MS), Methanothrix soehngenii, Methanospirillum hungatei, Methanogenium organophilum, and Methanococcus voltae. Cell extracts of H2/CO2 grown M. barkeri and of methanol grown M. barkeri showed the same specific activities suggesting that the four enzymes are of equal importance in CO2 reduction to methane and in methanol disproportionation to CO2 and CH4. In contrast, cell extracts of acetate grown M. barkeri exhibited much lower activities of formylmethanofuran dehydrogenase and methylenetetrahydromethanopterin dehydrogenase suggesting that these two enzymes are not involved in methanogenesis from acetate. In M. stadtmanae, which grows on H2 and methanol, only heterodisulfide reductase was detected in activities sufficient to account for the in vivo methane formation rate. This finding is consistent with the view that the three other oxidoreductases are not required for methanol reduction to methane with H2.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00244962
    Location Call Number Limitation Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...