scholarly journals Staphylococcus aureus Transcriptome Data and Metabolic Modelling Investigate the Interplay of Ser/Thr Kinase PknB, Its Phosphatase Stp, the glmR/yvcK Regulon and the cdaA Operon for Metabolic Adaptation

2021 ◽  
Vol 9 (10) ◽  
pp. 2148
Author(s):  
Chunguang Liang ◽  
Ana Rios-Miguel ◽  
Marcel Jarick ◽  
Priya Neurgaonkar ◽  
Myriam Girard ◽  
...  
Keyword(s):  
Amino Acid ◽  
Aromatic Amino Acid ◽  
Acid Synthesis ◽  
Aureus Strain ◽  
Metabolic Adaptation ◽  
Wild Type ◽  
Amino Acid Synthesis ◽  
Metabolic Modelling ◽  
Pyrimidine Synthesis ◽  
Cell Functions

Serine/threonine kinase PknB and its corresponding phosphatase Stp are important regulators of many cell functions in the pathogen S. aureus. Genome-scale gene expression data of S. aureus strain NewHG (sigB+) elucidated their effect on physiological functions. Moreover, metabolic modelling from these data inferred metabolic adaptations. We compared wild-type to deletion strains lacking pknB, stp or both. Ser/Thr phosphorylation of target proteins by PknB switched amino acid catabolism off and gluconeogenesis on to provide the cell with sufficient components. We revealed a significant impact of PknB and Stp on peptidoglycan, nucleotide and aromatic amino acid synthesis, as well as catabolism involving aspartate transaminase. Moreover, pyrimidine synthesis was dramatically impaired by stp deletion but only slightly by functional loss of PknB. In double knockouts, higher activity concerned genes involved in peptidoglycan, purine and aromatic amino acid synthesis from glucose but lower activity of pyrimidine synthesis from glucose compared to the wild type. A second transcriptome dataset from S. aureus NCTC 8325 (sigB-) validated the predictions. For this metabolic adaptation, PknB was found to interact with CdaA and the yvcK/glmR regulon. The involved GlmR structure and the GlmS riboswitch were modelled. Furthermore, PknB phosphorylation lowered the expression of many virulence factors, and the study shed light on S. aureus infection processes.

Intermediate Transport in Aromatic Amino Acid Synthesis of Higher Plants

Planta Medica ◽  
1990 ◽  
Vol 56 (06) ◽  
pp. 597-597
Author(s):  
G. Schultz ◽  
C. Leuschner ◽  
C. Schmidt ◽  
U. Homeyer
Keyword(s):  
Amino Acid ◽  
Aromatic Amino Acid ◽  
Higher Plants ◽  
Acid Synthesis ◽  
Amino Acid Synthesis

scholarly journals A Novelmeso-Diaminopimelate Dehydrogenase from Symbiobacterium thermophilum: Overexpression, Characterization, and Potential for d-Amino Acid Synthesis

2012 ◽  
Vol 78 (24) ◽  
pp. 8595-8600 ◽  
Author(s):  
Xiuzhen Gao ◽  
Xi Chen ◽  
Weidong Liu ◽  
Jinhui Feng ◽  
Qiaqing Wu ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Substrate Specificity ◽  
Enantiomeric Excess ◽  
Acid Synthesis ◽  
Amino Acid Residues ◽  
Wild Type ◽  
Gene Encoding ◽  
Amino Acid Synthesis ◽  
Content Type

ABSTRACTmeso-Diaminopimelate dehydrogenase (meso-DAPDH) is an NADP+-dependent enzyme which catalyzes the reversible oxidative deamination on thed-configuration ofmeso-2,6-diaminopimelate to producel-2-amino-6-oxopimelate. In this study, the gene encoding ameso-diaminopimelate dehydrogenase fromSymbiobacterium thermophilumwas cloned and expressed inEscherichia coli. In addition to the native substratemeso-2,6-diaminopimelate, the purified enzyme also showed activity towardd-alanine,d-valine, andd-lysine. This enzyme catalyzed the reductive amination of 2-keto acids such as pyruvic acid to generated-amino acids in up to 99% conversion and 99% enantiomeric excess. Sincemeso-diaminopimelate dehydrogenases are known to be specific tomeso-2,6-diaminopimelate, this is a unique wild-typemeso-diaminopimelate dehydrogenase with a more relaxed substrate specificity and potential ford-amino acid synthesis. The enzyme is the most stablemeso-diaminopimelate dehydrogenase reported to now. Two amino acid residues (F146 and M152) in the substrate binding sites ofS. thermophilum meso-DAPDH different from the sequences of other knownmeso-DAPDHs were replaced with the conserved amino acids in othermeso-DAPDHs, and assay of wild-type and mutant enzyme activities revealed that F146 and M152 are not critical in determining the enzyme's substrate specificity. The high thermostability and relaxed substrate profile ofS. thermophilum meso-DAPDH warrant it as an excellent starting enzyme for creating effectived-amino acid dehydrogenases by protein engineering.

Effects of Glyphosate on the Metabolism of Phenolic Compounds: VII. Root-Fed Amino Acids and Glyphosate Toxicity in Soybean (Glycine max) Seedlings

Weed Science ◽  
1981 ◽  
Vol 29 (3) ◽  
pp. 297-302 ◽  
Author(s):  
S. O. Duke ◽  
R. E. Hoagland
Keyword(s):  
Amino Acids ◽  
Glycine Max ◽  
Amino Acid ◽  
Phenolic Compounds ◽  
Aromatic Amino Acid ◽  
Aromatic Amino Acids ◽  
Acid Synthesis ◽  
Root Growth Inhibition ◽  
Shikimate Dehydrogenase ◽  
Amino Acid Synthesis

Several regimes of supplying exogenous aromatic amino acids to intact, 3-day-old, soybean [Glycine max(L.) Merr. ‘Hill’] seedlings by root uptake were tested to determine if growth retardation caused by root-fed, 0.5 mM glyphosate [N-(phosphonomethyl) glycine] could be reversed. Generally, root-fed levels of aromatic amino acids just below growth-retarding levels (e.g. 1 mM phenylalanine + 0.1 mM tyrosine) reversed root growth inhibition caused by glyphosate to a small (ca. 10%) but significant extent. Feeding aromatic amino acids for 1 to 3 days before glyphosate exposure did not enhance the reversal. Uptake and metabolism of root-fed, aromatic amino acids in control and glyphosate-treated plants were verified by increased levels of hydroxyphenolic compounds (end products of aromatic amino acid metabolism) and by uptake and incorporation of14C-labeled phenylalanine and tyrosine. On a fresh weight basis, glyphosate had no inhibitory effect on uptake or incorporation of these amino acids into protein or secondary phenolic compounds. After 3 days of exposure, glyphosate had no substantial effects on shikimate dehydrogenase activity in control or aromatic amino acid-fed seedlings. These data suggest that either root-fed aromatic amino acids are compartmentalized differently than the endogenous pools affected by glyphosate or that root-fed glyphosate exerts most of its effect on growth of soybean seedlings through means other than inhibition of aromatic amino acid synthesis.

scholarly journals Amino Acid Synthesis Is Necessary for Tomato Root Colonization by Pseudomonas fluorescens Strain WCS365

1997 ◽  
Vol 10 (1) ◽  
pp. 102-106 ◽  
Author(s):  
Marco Simons ◽  
Hjalmar P. Permentier ◽  
Letty A. de Weger ◽  
Carel A. Wijffelman ◽  
Ben J. J. Lugtenberg
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Root Exudate ◽  
Wild Type Strain ◽  
Acid Synthesis ◽  
Root Tip ◽  
Wild Type ◽  
Tomato Root ◽  
Amino Acid Synthesis ◽  
Auxotrophic Mutants

In this work the bio-availability of amino acids for the root-colonizing Pseudomonas fluorescens strain WCS365 in the tomato rhizosphere was studied. The amino acid composition of axenically collected tomato root exudate was determined. The results show that aspartic acid, glutamic acid, isoleucine, leucine, and lysine are the major amino acid components. The concentrations of individual amino acids in the rhizosphere of gnotobiotically grown tomato plants were estimated and considered to be too low to support growth of rhizosphere micro-organisms to numbers usually found in the tomato rhizosphere. To test this experimentally, mutants of P. fluorescens WCS365 auxotrophic for the amino acids leucine, arginine, histidine, isoleucine plus valine, and tryptophan were isolated after mutagenesis with Tn5lacZ. Root tip colonization of these mutants was measured after inoculation of germinated tomato seeds and subsequent growth in a gnotobiotic quartz sand system (M. Simons, A. J. van der Bij, I. Brand, L. A. de Weger, C. A. Wijffelman, and B. J. J. Lugtenberg. 1996. Gnotobiotic system for studying rhizo-sphere colonization by plant growth-promoting Pseudomonas bacteria. Mol. Plant-Microbe Interact. 9:600–607). In contrast to the wild-type strain, none of the five amino acid auxotrophs tested was able to colonize the tomato root tip, neither alone nor after co-inoculation with the wild-type strain. However, addition of the appropriate amino acid to the system restored colonization by the auxotrophic mutants, usually to wild-type levels. Analysis of the root base showed that cells of auxotrophic mutants were still present there. The results show that, although amino acids are present in root exudate, the bio-availability of the tested amino acids is too low to support root tip colonization by auxotrophic mutants of P. fluorescens strain WCS365. The genes that are required for amino acid synthesis are therefore necessary for root colonization. Moreover, these compounds apparently play no major role as nutrients in the tomato rhizosphere.

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