A multigene family of glycosyltransferases in a model plant, Arabidopsis thaliana

2002 ◽  
Vol 30 (2) ◽  
pp. 301-306 ◽  
Author(s):  
D. Bowles
Keyword(s):  
Arabidopsis Thaliana ◽  
Multigene Family ◽  
Sequence Similarity ◽  
Plant Cells ◽  
The Family ◽  
Model Plant Arabidopsis Thaliana ◽  
Group 1 ◽  
Plant Arabidopsis Thaliana

Glycosyltransferases transfer sugars from NDP-sugar donors to acceptors. The multigene family of transferases described in this paper typically transfer glucose from UDP-glucose to low-molecular-mass acceptors in the cytosol of plant cells. There are 107 sequences in the genome of Arabidopsis thaliana that contain a consensus, suggesting they belong to this Group 1 multigene family. The family has been analysed phylogenetically, and a functional genomics approach has been applied to explore the relatedness of sequence similarity to catalytic specificity and stereoselectivity. Enzymes belonging to this class of transferases glycosylate a vast array of acceptors, including natural products such as secondary metabolites and hormones, as well as xenobiotics absorbed by the plant, such as herbicides and pesticides. Conjugation to glucose potentially changes the activity of the acceptor molecule and invariably changes its location within the plant cell. Using the genomics approach described, a platform of knowledge has been constructed that will enable an understanding to be gained on the role of these enzymes in cellular homoeostasis, as well as their activity in biotransformations in vitro that require strict regioselectivity of glycosylation.

Role of miRNAs in root development of model plant Arabidopsis thaliana

2017 ◽  
Vol 22 (4) ◽  
pp. 382-392 ◽  
Author(s):  
Vibhav Gautam ◽  
Archita Singh ◽  
Swati Verma ◽  
Ashutosh Kumar ◽  
Pramod Kumar ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Root Development ◽  
Model Plant ◽  
Model Plant Arabidopsis Thaliana ◽  
Plant Arabidopsis Thaliana

scholarly journals The AtNFS2 gene from Arabidopsis thaliana encodes a NifS-like plastidial cysteine desulphurase

2002 ◽  
Vol 366 (2) ◽  
pp. 557-564 ◽  
Author(s):  
Sébastien LÉON ◽  
Brigitte TOURAINE ◽  
Jean-François BRIAT ◽  
Stéphane LOBRÉAUX
Keyword(s):  
Arabidopsis Thaliana ◽  
Cluster Assembly ◽  
Synechocystis Pcc 6803 ◽  
Major Site ◽  
Reverse Transcription Pcr ◽  
Gfp Fusion Protein ◽  
Model Plant Arabidopsis Thaliana ◽  
Cluster Biosynthesis ◽  
Plant Arabidopsis Thaliana

NifS-like proteins are cysteine desulphurases required for the mobilization of sulphur from cysteine. They are present in all organisms, where they are involved in iron–sulphur (Fe–S) cluster biosynthesis. In eukaryotes, these enzymes are present in mitochondria, which are the major site for Fe–S cluster assembly. The genome of the model plant Arabidopsis thaliana contains two putative NifS-like proteins. A cDNA corresponding to one of them was cloned by reverse-transcription PCR, and named AtNFS2. The corresponding transcript is expressed in many plant tissues. It encodes a protein highly related (75% similarity) to the slr0077-gene product from Synechocystis PCC 6803, and is predicted to be targeted to plastids. Indeed, a chimaeric AtNFS2–GFP fusion protein, containing one-third of AtNFS2 from its N-terminal end, was addressed to chloroplasts. Overproduction in Escherichia coli and purification of recombinant AtNFS2 protein enabled one to demonstrate that it bears a pyridoxal 5′-phosphate-dependent cysteine desulphurase activity in vitro, thus being the first NifS homologue characterized to date in plants. The putative physiological functions of this gene are discussed, including the attractive hypothesis of a possible role in Fe–S cluster assembly in plastids.

The role of cytochrome P450 enzymes in the biosynthesis of camalexin

2006 ◽  
Vol 34 (6) ◽  
pp. 1206-1208 ◽  
Author(s):  
E. Glawischnig
Keyword(s):  
Arabidopsis Thaliana ◽  
Cytochrome P450 ◽  
Biosynthetic Pathway ◽  
Model System ◽  
Biosynthetic Gene ◽  
Cytochrome P450 Enzymes ◽  
Model Plant Arabidopsis Thaliana ◽  
Phytoalexin Biosynthesis ◽  
Plant Arabidopsis Thaliana

The biosynthesis of camalexin, the main phytoalexin of the model plant Arabidopsis thaliana, involves at least two CYP (cytochrome P450) steps. It is synthesized from tryptophan via indole-3-acetaldoxime in a reaction catalysed by CYP79B2 and CYP79B3. Based on the pad3 mutant phenotype, CYP71B15 (PAD3) had also been suggested as a camalexin biosynthetic gene. CYP71B15 catalyses the final step in camalexin biosynthesis, as recombinant CYP71B15 and microsomes from Arabidopsis leaves expressing functional PAD3 converted dihydrocamalexic acid into camalexin. The biosynthetic pathway is co-ordinately induced, strictly localized to the site of pathogen infection. This provides a model system to study the regulation of CYP enzymes involved in phytoalexin biosynthesis.

Glutathionylation of cytosolic glyceraldehyde-3-phosphate dehydrogenase from the model plant Arabidopsis thaliana is reversed by both glutaredoxins and thioredoxins in vitro

2012 ◽  
Vol 445 (3) ◽  
pp. 337-347 ◽  
Author(s):  
Mariette Bedhomme ◽  
Mattia Adamo ◽  
Christophe H. Marchand ◽  
Jérémy Couturier ◽  
Nicolas Rouhier ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Redox State ◽  
Irreversible Process ◽  
Reduced Glutathione ◽  
Eukaryotic Cells ◽  
Control Of Gene Expression ◽  
Mixed Disulfide ◽  
Model Plant Arabidopsis Thaliana ◽  
Plant Arabidopsis Thaliana

Plants contain both cytosolic and chloroplastic GAPDHs (glyceraldehyde-3-phosphate dehydrogenases). In Arabidopsis thaliana, cytosolic GAPDH is involved in the glycolytic pathway and is represented by two differentially expressed isoforms (GapC1 and GapC2) that are 98% identical in amino acid sequence. In the present study we show that GapC1 is a phosphorylating NAD-specific GAPDH with enzymatic activity strictly dependent on Cys149. Catalytic Cys149 is the only solvent-exposed cysteine of the protein and its thiol is relatively acidic (pKa=5.7). This property makes GapC1 sensitive to oxidation by H2O2, which appears to inhibit enzyme activity by converting the thiolate of Cys149 (–S−) into irreversible oxidized forms (–SO2− and –SO3−) via a labile sulfenate intermediate (–SO−). GSH (reduced glutathione) prevents this irreversible process by reacting with Cys149 sulfenates to give rise to a mixed disulfide (Cys149–SSG), as demonstrated by both MS and biotinylated GSH. Glutathionylated GapC1 can be fully reactivated either by cytosolic glutaredoxin, via a GSH-dependent monothiol mechanism, or, less efficiently, by cytosolic thioredoxins physiologically reduced by NADPH:thioredoxin reductase. The potential relevance of these findings is discussed in the light of the multiple functions of GAPDH in eukaryotic cells (e.g. glycolysis, control of gene expression and apoptosis) that appear to be influenced by the redox state of the catalytic Cys149.

scholarly journals The scope of flavin-dependent reactions and processes in the model plant Arabidopsis thaliana

2021 ◽  
Vol 189 ◽  
pp. 112822
Author(s):  
Reinmar Eggers ◽  
Alexandra Jammer ◽  
Shalinee Jha ◽  
Bianca Kerschbaumer ◽  
Majd Lahham ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Model Plant ◽  
Model Plant Arabidopsis Thaliana ◽  
Plant Arabidopsis Thaliana

scholarly journals Legionella pneumophila CRISPR-Cas suggests recurrent encounters with one or more phages in the family Microviridae .

2021 ◽  
Author(s):  
Shayna R. Deecker ◽  
Malene L. Urbanus ◽  
Beth Nicholson ◽  
Alexander W. Ensminger
Keyword(s):  
Legionella Pneumophila ◽  
Sequence Similarity ◽  
Mobile Element ◽  
Current Data ◽  
Significant Sequence Similarity ◽  
Remediation Strategies ◽  
The Family ◽  
Legionnaires Disease ◽  
Outstanding Question

Legionella pneumophila is a ubiquitous freshwater pathogen and the causative agent of Legionnaires’ disease. L. pneumophila growth within protists provides a refuge from desiccation, disinfection, and other remediation strategies. One outstanding question has been whether this protection extends to phages. L. pneumophila isolates are remarkably devoid of prophages and to date no Legionella phages have been identified. Nevertheless, many L. pneumophila isolates maintain active CRISPR-Cas defenses. So far, the only known target of these systems is an episomal element that we previously named Legionella Mobile Element-1 (LME-1). The continued expansion of publicly available genomic data promises to further our understanding of the role of these systems. We now describe over 150 CRISPR-Cas systems across 600 isolates to establish the clearest picture yet of L. pneumophila ’s adaptive defenses. By searching for targets of 1,500 unique CRISPR-Cas spacers, LME-1 remains the only identified CRISPR-Cas targeted integrative element. We identified 3 additional LME-1 variants - all targeted by previously and newly identified CRISPR-Cas spacers - but no other similar elements. Notably, we also identified several spacers with significant sequence similarity to microviruses, specifically those within the subfamily Gokushovirinae . These spacers are found across several different CRISPR-Cas arrays isolated from geographically diverse isolates, indicating recurrent encounters with these phages. Our analysis of the extended Legionella CRISPR-Cas spacer catalog leads to two main conclusions: current data argue against CRISPR-Cas targeted integrative elements beyond LME-1, and the heretofore unknown L. pneumophila phages are most likely lytic gokushoviruses. IMPORTANCE Legionnaires’ disease is an often-fatal pneumonia caused by Legionella pneumophila , which normally grows inside amoebae and other freshwater protists. L. pneumophila trades diminished access to nutrients for the protection and isolation provided by the host. One outstanding question is whether L. pneumophila is susceptible to phages, given the protection provided by its intracellular lifestyle. In this work, we use Legionella CRISPR spacer sequences as a record of phage infection to predict that the “missing” L. pneumophila phages belong to the microvirus subfamily Gokushovirinae . Gokushoviruses are known to infect another intracellular pathogen, Chlamydia . How do gokushoviruses access L. pneumophila (and Chlamydia ) inside their “cozy niches”? Does exposure to phages happen during a transient extracellular period (during cell-to-cell spread) or is it indicative of a more complicated environmental lifestyle? One thing is clear, 100 years after their discovery, phages continue to hold important secrets about the bacteria upon which they prey.

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