Disease relevance of AtSerat2;1

• To obtain cDNA encoding the isoforms, functional complementation experiments were performed using an Arabidopsis thaliana expression library and an Escherichia coli mutant devoid of serine acetyltransferase activity [1].

High impact information on AtSerat2;1

• Further analysis of the Austrian Ni hyperaccumulator T. goesingense revealed that the high concentrations of OAS, Cys, and GSH observed in this hyperaccumulator coincide with constitutively high activity of both serine acetyltransferase (SAT) and glutathione reductase [2].
• By contrast, SAT-p and SAT-m were feedback inhibition-insensitive isozymes [3].
• Isoform-dependent differences in feedback regulation and subcellular localization of serine acetyltransferase involved in cysteine biosynthesis from Arabidopsis thaliana [3].
• Elevation of free SA levels in Arabidopsis, both genetically and by exogenous feeding, enhances the specific activity of serine acetyltransferase, leading to elevated glutathione and increased Ni resistance [4].
• Tracer experiments using (35)SO(4)(2-) in the presence of 0.5 mm L-cysteine or GSH showed that both thiols decreased sulphate uptake, APR activity and the flux of label into cysteine, GSH and protein, but had no effect on the activity of all other enzymes of assimilatory sulphate reduction and serine acetyltransferase [5].

Chemical compound and disease context of AtSerat2;1

• SAT1 has been cloned into the pGEX plasmid, expressed in E. coli and SAT activity of the recombinant enzyme has been measured as acetyl-CoA hydrolysis detected at 232 nm [6].

Biological context of AtSerat2;1

• The predicted amino acid sequence shows that it encodes a polypeptide of M(r) 34,330 exhibiting 41% amino acid identity with the E. coli serine acetyltransferase [1].
• This strategy allowed isolation of three distinct cDNAs encoding serine acetyltransferase isoforms, as confirmed by enzyme activity measurements, genomic hybridizations, and nucleotide sequencing [1].
• Production of cysteine for bacterial and plant biotechnology: application of cysteine feedback-insensitive isoforms of serine acetyltransferase [7].
• We have previously cloned a cDNA, designated SAT1, corresponding to a gene coding for a serine acetyltransferase (SAT) from onion (Allium cepa L.). The SAT1 locus was mapped to chromosome 7 of onion using a single-stranded conformation polymorphism (SSCP) in the 3' UTR of the gene [6].
• Reported here is a cDNA corresponding to one of these genes, SAT1, a 1,079 bp clone with an open reading frame predicted to encode a 34-kDa protein that is able to functionally complement a serine acetyltransferase mutant strain of Escherichia coli [8].

Anatomical context of AtSerat2;1

• The intracellular compartmentation of serine acetyltransferase, a key enzyme in the L-cysteine biosynthesis pathway, has been investigated in pea (Pisum sativum) leaves, by isolation of organelles and fractionation of protoplasts [1].
• The first 40 amino acids of the SAT1 polypeptide resembles a plastid transit peptide, but the polypeptide is probably not plastid localized [8].

Associations of AtSerat2;1 with chemical compounds

• The serine acetyltransferase gene family in Arabidopsis thaliana and the regulation of its expression by cadmium [9].
• Serine acetyltransferase (SATase; EC 2.3.1.30) catalyzes the formation of O-acetylserine from L-Ser and acetyl-CoA in plants and bacteria [10].
• The first step of cysteine biosynthesis in bacteria and plants consists in the formation of O-acetylserine catalyzed by serine acetyltransferase (SAT) [7].
• Phylogenetic analysis has placed SAT1 in a strongly supported group (100% bootstrap) that comprises sequences that have been characterised biochemically, including Allium tuberosum, Spinacea oleracea, Glycine max, Citrullus vulgaris, and SAT5 (AT5g56760) of Arabidopsis thaliana [6].
• The predicted amino acid sequence of SAT1 shows significant homology with bacterial serine acetyltransferases [8].

Other interactions of AtSerat2;1

• It is accomplished by the sequential reaction of two enzymes, serine acetyltransferase (SAT) and O-acetylserine (thiol) lyase (OAS-TL) [11].

References