Inhibition of Bacteriochlorophyll Biosynthesis by Gabaculin (3-Amino, 2,3-dihydrobenzoic Acid) and Presence of an Enzyme of the C5-Pathway of δ-Aminolevulinate Synthesis in Chloroflexus aurantiacus

1989 ◽  
Vol 44 (1-2) ◽  
pp. 77-80 ◽  
Author(s):  
Monika Kern ◽  
Jobst-Heinrich Klemme
Keyword(s):  
Chloroflexus Aurantiacus ◽  
Bacteriochlorophyll C ◽  
Cell Extracts ◽  
Highly Sensitive ◽  
Key Enzyme ◽  
C5 Pathway ◽  
Bacteriochlorophyll Biosynthesis

Abstract Biosynthesis of bacteriochlorophyll c and a in the thermophilic phototrophic prokaryote. Chloroflexus aurantiacus Ok-70-fl, was strongly inhibited by the antibiotic gabaculin (3-amino 2,3- dihydrobenzoic acid), an inhibitor of the glutamate-C5-pathway of ö-aminolevulinate (ALA) synthesis. The key enzyme of the Shemin-pathway of ALA formation, ALA synthase (EC 2.3.1.37), was not detected in cell extracts of Chi. aurantiacus. However, the extracts catalyzed ALA formation from glutamate 1-semialdehyde, a reaction being highly sensitive to gabaculin.

scholarly journals Key Aromatic-Ring-Cleaving Enzyme, Protocatechuate 3,4-Dioxygenase, in the Ecologically Important MarineRoseobacter Lineage

2000 ◽  
Vol 66 (11) ◽  
pp. 4662-4672 ◽  
Author(s):  
Alison Buchan ◽  
Lauren S. Collier ◽  
Ellen L. Neidle ◽  
Mary Ann Moran
Keyword(s):  
Aromatic Compounds ◽  
Southern Hybridization ◽  
Ring Cleavage ◽  
Degenerate Pcr ◽  
Cell Extracts ◽  
Aromatic Compound Degradation ◽  
Genes Encoding ◽  
Cleavage Enzyme ◽  
Key Enzyme ◽  
Dioxygenase Activity

ABSTRACT Aromatic compound degradation in six bacteria representing an ecologically important marine taxon of the α-proteobacteria was investigated. Initial screens suggested that isolates in theRoseobacter lineage can degrade aromatic compounds via the β-ketoadipate pathway, a catabolic route that has been well characterized in soil microbes. Six Roseobacter isolates were screened for the presence of protocatechuate 3,4-dioxygenase, a key enzyme in the β-ketoadipate pathway. All six isolates were capable of growth on at least three of the eight aromatic monomers presented (anthranilate, benzoate, p-hydroxybenzoate, salicylate, vanillate, ferulate, protocatechuate, and coumarate). Four of the Roseobacter group isolates had inducible protocatechuate 3,4-dioxygenase activity in cell extracts when grown onp-hydroxybenzoate. The pcaGH genes encoding this ring cleavage enzyme were cloned and sequenced from two isolates,Sagittula stellata E-37 and isolate Y3F, and in both cases the genes could be expressed in Escherichia coli to yield dioxygenase activity. Additional genes involved in the protocatechuate branch of the β-ketoadipate pathway (pcaC,pcaQ, and pobA) were found to cluster withpcaGH in these two isolates. Pairwise sequence analysis of the pca genes revealed greater similarity between the twoRoseobacter group isolates than between genes from eitherRoseobacter strain and soil bacteria. A degenerate PCR primer set targeting a conserved region within PcaH successfully amplified a fragment of pcaH from two additionalRoseobacter group isolates, and Southern hybridization indicated the presence of pcaH in the remaining two isolates. This evidence of protocatechuate 3,4-dioxygenase and the β-ketoadipate pathway was found in all six Roseobacterisolates, suggesting widespread abilities to degrade aromatic compounds in this marine lineage.

Incorporation of exogenous long-chain alcohols into bacteriochlorophyll c homologs by Chloroflexus aurantiacus

1995 ◽  
Vol 163 (2) ◽  
pp. 119-123 ◽  
Author(s):  
Kim Lambertsen Larsen ◽  
Mette Miller ◽  
Raymond P. Cox
Keyword(s):  
Chloroflexus Aurantiacus ◽  
Bacteriochlorophyll C ◽  
Long Chain

Deoxyribonucleotide Synthesis in Phycovirus-Infected Green Algae. A New Virus-Induced Ribonucleotide Reductase

1993 ◽  
Vol 48 (1-2) ◽  
pp. 113-118 ◽  
Author(s):  
Claus Bornemann ◽  
Hartmut Follmann
Keyword(s):  
Green Algae ◽  
Ribonucleotide Reductase ◽  
Fold Increase ◽  
Optimum Concentration ◽  
Characteristic Parameters ◽  
Temperature Optimum ◽  
Allosteric Effector ◽  
Cell Extracts ◽  
Key Enzyme

Infection of Chlorella-like green algae with freshwater phycoviruses is associated with a large and rapid demand for DNA precursors which cannot be met by the algal deoxyribonucleotide-synthesizing enzymes. We have demonstrated in these cells an up to ten-fold increase of the key enzyme, ribonucleotide reductase, 1-2 h post infection. The enzyme activity has been partially enriched from cell extracts. In vitro, it differs from that of uninfected algae in three characteristic parameters, viz. eight-fold higher resistance to millimolar hydroxyurea concentrations, much higher optimum concentration of an allosteric effector nucleotide, thymidine triphosphate, and an unusually low temperature optimum at 20 °C. We conclude that the large DNA phycoviruses, like Herpes and pox viruses, code for their own specific ribonucleotide reductase.

scholarly journals The Nonphosphorylative Entner-Doudoroff Pathway in the Thermoacidophilic Euryarchaeon Picrophilus torridus Involves a Novel 2-Keto-3-Deoxygluconate- Specific Aldolase

2009 ◽  
Vol 192 (4) ◽  
pp. 964-974 ◽  
Author(s):  
Matthias Reher ◽  
Tobias Fuhrer ◽  
Michael Bott ◽  
Peter Schönheit
Keyword(s):  
Amino Acid ◽  
Catalytic Efficiency ◽  
Start Codon ◽  
Ionization Time ◽  
Cell Extracts ◽  
Translation Start ◽  
Picrophilus Torridus ◽  
Key Enzyme ◽  
Kdpg Aldolase

ABSTRACT The pathway of glucose degradation in the thermoacidophilic euryarchaeon Picrophilus torridus has been studied by in vivo labeling experiments and enzyme analyses. After growth of P. torridus in the presence of [1-13C]- and [3-13C]glucose, the label was found only in the C-1 and C-3 positions, respectively, of the proteinogenic amino acid alanine, indicating the exclusive operation of an Entner-Doudoroff (ED)-type pathway in vivo. Cell extracts of P. torridus contained all enzyme activities of a nonphosphorylative ED pathway, which were not induced by glucose. Two key enzymes, gluconate dehydratase (GAD) and a novel 2-keto-3-deoxygluconate (KDG)-specific aldolase (KDGA), were characterized. GAD is a homooctamer of 44-kDa subunits, encoded by Pto0485. KDG aldolase, KDGA, is a homotetramer of 32-kDa subunits. This enzyme was highly specific for KDG with up to 2,000-fold-higher catalytic efficiency compared to 2-keto-3-deoxy-6-phosphogluconate (KDPG) and thus differs from the bifunctional KDG/KDPG aldolase, KD(P)GA of crenarchaea catalyzing the conversion of both KDG and KDPG with a preference for KDPG. The KDGA-encoding gene, kdgA, was identified by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS) as Pto1279, and the correct translation start codon, an ATG 24 bp upstream of the annotated start codon of Pto1279, was determined by N-terminal amino acid analysis. The kdgA gene was functionally overexpressed in Escherichia coli. Phylogenetic analysis revealed that KDGA is only distantly related to KD(P)GA, both enzymes forming separate families within the dihydrodipicolinate synthase superfamily. From the data we conclude that P. torridus degrades glucose via a strictly nonphosphorylative ED pathway with a novel KDG-specific aldolase, thus excluding the operation of the branched ED pathway involving a bifunctional KD(P)GA as a key enzyme.

scholarly journals Autotrophic Carbon Dioxide Fixation via the Calvin-Benson-Bassham Cycle by the Denitrifying Methanotroph “Candidatus Methylomirabilis oxyfera”

2014 ◽  
Vol 80 (8) ◽  
pp. 2451-2460 ◽  
Author(s):  
Olivia Rasigraf ◽  
Dorien M. Kool ◽  
Mike S. M. Jetten ◽  
Jaap S. Sinninghe Damsté ◽  
Katharina F. Ettwig
Keyword(s):  
Carbon Dioxide ◽  
Enrichment Culture ◽  
Carbon Assimilation ◽  
Carbon Dioxide Fixation ◽  
Oxidation Activity ◽  
Bisphosphate Carboxylase ◽  
Content Type ◽  
Whole Cells ◽  
Cell Extracts ◽  
Key Enzyme

ABSTRACTMethane is an important greenhouse gas and the most abundant hydrocarbon in the Earth's atmosphere. Methanotrophic microorganisms can use methane as their sole energy source and play a crucial role in the mitigation of methane emissions in the environment. “CandidatusMethylomirabilis oxyfera” is a recently described intra-aerobic methanotroph that is assumed to use nitric oxide to generate internal oxygen to oxidize methane via the conventional aerobic pathway, including the monooxygenase reaction. Previous genome analysis has suggested that, like the verrucomicrobial methanotrophs, “Ca.Methylomirabilis oxyfera” encodes and transcribes genes for the Calvin-Benson-Bassham (CBB) cycle for carbon assimilation. Here we provide multiple independent lines of evidence for autotrophic carbon dioxide fixation by “Ca.Methylomirabilis oxyfera” via the CBB cycle. The activity of ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO), a key enzyme of the CBB cycle, in cell extracts from an “Ca.Methylomirabilis oxyfera” enrichment culture was shown to account for up to 10% of the total methane oxidation activity. Labeling studies with whole cells in batch incubations supplied with either13CH4or [13C]bicarbonate revealed that “Ca.Methylomirabilis oxyfera” biomass and lipids became significantly more enriched in13C after incubation with13C-labeled bicarbonate (and unlabeled methane) than after incubation with13C-labeled methane (and unlabeled bicarbonate), providing evidence for autotrophic carbon dioxide fixation. Besides this experimental approach, detailed genomic and transcriptomic analysis demonstrated an operational CBB cycle in “Ca.Methylomirabilis oxyfera.” Altogether, these results show that the CBB cycle is active and plays a major role in carbon assimilation by “Ca.Methylomirabilis oxyfera” bacteria. Our results suggest that autotrophy might be more widespread among methanotrophs than was previously assumed and implies that a methanotrophic community in the environment is not necessarily revealed by13C-depleted lipids.

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