scholarly journals Biosynthesis of ribose-5-phosphate and erythrose-4-phosphate in archaea: a phylogenetic analysis of archaeal genomes

Archaea ◽  
2005 ◽  
Vol 1 (5) ◽  
pp. 347-352 ◽  
Author(s):  
Tim Soderberg
Keyword(s):  
Amino Acids ◽  
Phylogenetic Analysis ◽  
Biosynthetic Pathway ◽  
Aromatic Amino Acids ◽  
Amino Acid Biosynthesis ◽  
Pentose Phosphate ◽  
Acid Biosynthesis ◽  
Potential Explanation ◽  
Archaeal Species ◽  
Genes Encoding

A phylogenetic analysis of the genes encoding enzymes in the pentose phosphate pathway (PPP), the ribulose monophosphate (RuMP) pathway, and the chorismate pathway of aromatic amino acid biosynthesis, employing data from 13 complete archaeal genomes, provides a potential explanation for the enigmatic phylogenetic patterns of the PPP genes in archaea. Genomic and biochemical evidence suggests that three archaeal species (Methanocaldococcus jannaschii,Thermoplasma acidophilumandThermoplasma volcanium) produce ribose-5-phosphate via the nonoxidative PPP (NOPPP), whereas nine species apparently lack an NOPPP but may employ a reverse RuMP pathway for pentose synthesis. One species (Halobacteriumsp. NRC-1) lacks both the NOPPP and the RuMP pathway but may possess a modified oxidative PPP (OPPP), the details of which are not yet known. The presence of transketolase in several archaeal species that are missing the other two NOPPP genes can be explained by the existence of differing requirements for erythrose-4-phosphate (E4P) among archaea: six species use transketolase to make E4P as a precursor to aromatic amino acids, six species apparently have an alternate biosynthetic pathway and may not require the ability to make E4P, and one species (Pyrococcus horikoshii) probably does not synthesize aromatic amino acids at all.

scholarly journals Incorporation of alternative amino acids into cyanophycin by different cyanophycin synthetases heterologously expressed in Corynebacterium glutamicum

AMB Express ◽  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ramona Wördemann ◽  
Lars Wiefel ◽  
Volker F. Wendisch ◽  
Alexander Steinbüchel
Keyword(s):  
Amino Acids ◽  
Dry Weight ◽  
Growth Conditions ◽  
Amino Acid Biosynthesis ◽  
Water Soluble ◽  
Lysine Content ◽  
Polyaspartic Acid ◽  
Acid Biosynthesis ◽  
Cyanophycin Synthetase ◽  
Potential Precursor

AbstractCyanophycin (multi-l-arginyl-poly-l-aspartic acid; also known as cyanophycin grana peptide [CGP]) is a biopolymer that could be used in various fields, for example, as a potential precursor for the synthesis of polyaspartic acid or for the production of CGP-derived dipeptides. To extend the applications of this polymer, it is therefore of interest to synthesize CGP with different compositions. A recent re-evaluation of the CGP synthesis in C. glutamicum has shown that C. glutamicum is a potentially interesting microorganism for CGP synthesis with a high content of alternative amino acids. This study shows that the amount of alternative amino acids can be increased by using mutants of C. glutamicum with altered amino acid biosynthesis. With the DM1729 mutant, the lysine content in the polymer could be increased up to 33.5 mol%. Furthermore, an ornithine content of up to 12.6 mol% was achieved with ORN2(Pgdh4). How much water-soluble or insoluble CGP is synthesized is strongly related to the used cyanophycin synthetase. CphADh synthesizes soluble CGP exclusively. However, soluble CGP could also be isolated from cells expressing CphA6308Δ1 or CphA6308Δ1_C595S in addition to insoluble CGP in all examined strains. The point mutation in CphA6308Δ1_C595S partially resulted in a higher lysine content. In addition, the CGP content could be increased to 36% of the cell dry weight under optimizing growth conditions in C. glutamicum ATCC13032. All known alternative major amino acids for CGP synthesis (lysine, ornithine, citrulline, and glutamic acid) could be incorporated into CGP in C. glutamicum.

Effects of an Electric Field of Sinusoidal Waves on the Amino Acid Biosynthesis by Azotobacter

1980 ◽  
Vol 35 (3-4) ◽  
pp. 258-261
Author(s):  
A. Martin Gonzalez ◽  
M. T. Izquierdo
Keyword(s):  
Amino Acids ◽  
Nitrogen Fixation ◽  
Amino Acid ◽  
Electric Field ◽  
Electric Fields ◽  
Culture Medium ◽  
Azotobacter Vinelandii ◽  
Amino Acid Biosynthesis ◽  
Medium Composition ◽  
Acid Biosynthesis

Abstract Electric Field Electric fields of sinusoidal waves have been applied in cultures of Azotobacter vinelandii, with potentials between 0 V and 10 V, intensities from 0 mA to 16 mA and frequencies between 5 Hz and 200 KHz. The influence of the electric field of sinusoidal waves on the nitrogen fixation on the post­ culture medium composition has a maximum at 5 V, 8 mA and 20 Hz. The rate of synthesis of specific amino acids by Azotobacter depends on the frequency and potential of the electric field applied. The concentration of each amino acid present in the post-culture medium is increased according to the electric field employed and the amino acid biosynthesis in culture medium is activated during the first days of incubation.

The Gcn2–eIF2α pathway connects iron and amino acid homeostasis in Saccharomyces cerevisiae

2018 ◽  
Vol 475 (8) ◽  
pp. 1523-1534 ◽  
Author(s):  
Marcos Caballero-Molada ◽  
María D. Planes ◽  
Helena Benlloch ◽  
Sergio Atares ◽  
Miguel A. Naranjo ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Amino Acids ◽  
Amino Acid ◽  
Iron Content ◽  
Amino Acid Biosynthesis ◽  
Initiation Factor ◽  
Acid Biosynthesis ◽  
Yeast Saccharomyces Cerevisiae ◽  
Iron Sulfur ◽  
Amino Acid Homeostasis

In eukaryotic cells, amino acid biosynthesis is feedback-inhibited by amino acids through inhibition of the conserved protein kinase Gcn2. This decreases phosphorylation of initiation factor eIF2α, resulting in general activation of translation but inhibition of translation of mRNA for transcription factor (TF) Gcn4 in yeast or ATF4 in mammals. These TFs are positive regulators of amino acid biosynthetic genes. As several enzymes of amino acid biosynthesis contain iron–sulfur clusters (ISCs) and iron excess is toxic, iron and amino acid homeostasis should be co-ordinated. Working with the yeast Saccharomyces cerevisiae, we found that amino acid supplementation down-regulates expression of genes for iron uptake and decreases intracellular iron content. This cross-regulation requires Aft1, the major TF activated by iron scarcity, as well as Gcn2 and phosphorylatable eIF2α but not Gcn4. A mutant with constitutive activity of Gcn2 (GCN2c) shows less repression of iron transport genes by amino acids and increased nuclear localization of Aft1 in an iron-poor medium, and increases iron content in this medium. As Aft1 is activated by depletion of mitochondrial ISCs, it is plausible that the Gcn2–eIF2α pathway inhibits the formation of these complexes. Accordingly, the GCN2c mutant has strongly reduced activity of succinate dehydrogenase, an iron–sulfur mitochondrial enzyme, and is unable to grow in media with very low iron or with galactose instead of glucose, conditions where formation of ISCs is specially needed. This mechanism adjusts the uptake of iron to the needs of amino acid biosynthesis and expands the list of Gcn4-independent activities of the Gcn2–eIF2α regulatory system.

Effect of sugars on amino acid biosynthesis in maize root tips

1970 ◽  
Vol 48 (1) ◽  
pp. 117-124 ◽  
Author(s):  
Ann Oaks ◽  
F. J. Johnson
Keyword(s):  
Amino Acids ◽  
Tricarboxylic Acid Cycle ◽  
Major Effect ◽  
Amino Acid Biosynthesis ◽  
Maize Root ◽  
Root Tips ◽  
Acid Biosynthesis ◽  
General Increase ◽  
Amino Butyric Acid ◽  
Protein Amino Acids

There is a general increase in incorporation of acetate carbon when excised maize root tips are aged for 3 h in a salts medium, but little further increase during a subsequent 3-h period. Addition of glucose or sucrose to the medium causes a further increase in the incorporation of acetate carbon into glutamic acid, glutamine, γ-amino butyric acid and into the protein amino acids, principal among these being glutamic, aspartic, proline, threonine, valine and the leucines. Sugars also cause a reduced incorporation of acetate carbon into asparagine. The results indicate that glucose (or sucrose) has a major effect in diverting carbon of the tricarboxylic acid cycle into glutamine and protein amino acids and away from asparagine.

STUDIES ON THE BIOSYNTHESIS OF VOLUCRISPORIN: II. METABOLISM OF SOME PHENYLPROPANOID COMPOUNDS BY VOLUCRISPORA AURANTIACA HASKINS

1966 ◽  
Vol 44 (4) ◽  
pp. 403-413 ◽  
Author(s):  
P. Chandra ◽  
G. Read ◽  
L. C. Vining
Keyword(s):  
Amino Acids ◽  
Cinnamic Acid ◽  
Biosynthetic Pathway ◽  
Shikimic Acid ◽  
Aromatic Amino Acids ◽  
Hydroxycinnamic Acid ◽  
Phenyllactic Acid ◽  
Radioactive Substrate

DL-Phenyllactic acid-α-14C, DL-phenylserine-α-14C, L-phenylalanine-carboxyl-14C, and shikimic acid-U-14C were incorporated into phenylalanine and tyrosine isolated from mycelial hydrolysates of Volucrispora aurantiaca as well as into volucrisporin. DL-m-Tyrosine-carboxyl-14C was incorporated into volucrisporin but not into the aromatic amino acids. L-Tyrosine-β-14C, cinnamic acid-α-14C, and m-hydroxycinnamic acid-α-14C were metabolized by the fungus but did not serve as precursors of volucrisporin or of mycelial phenylalanine. The results are consistent with the concept of a biosynthetic pathway to volucrisporin via phenylpyruvic and m-hydroxyphenylpyruvic acids. Substantial amounts of each radioactive substrate fed to V. aurantiaca PRL 1952 were incorporated into a brown melanoid pigment.

scholarly journals Identification of Genes That Confer Sediment Fitness to Desulfovibrio desulfuricans G20

2007 ◽  
Vol 73 (19) ◽  
pp. 6305-6312 ◽  
Author(s):  
Qingwei Luo ◽  
Jennifer L. Groh ◽  
Jimmy D. Ballard ◽  
Lee R. Krumholz
Keyword(s):  
Signal Transduction ◽  
Dna Repair ◽  
Amino Acid ◽  
Desulfovibrio Desulfuricans ◽  
Amino Acid Biosynthesis ◽  
Hydrogenase Activity ◽  
Functional Categories ◽  
Acid Biosynthesis ◽  
Genes Encoding ◽  
Insertion Elements

ABSTRACT Signature-tagged mutants of Desulfovibrio desulfuricans G20 were screened, and 97 genes crucial for sediment fitness were identified. These genes belong to functional categories including signal transduction, binding and transport, insertion elements, and others. Mutants with mutations in genes encoding proteins involved in amino acid biosynthesis, hydrogenase activity, and DNA repair were further characterized.

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