Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:6.1.1.11 (seryl-tRNA synthetase)
 207 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Saccharomyces cerevisiae seryl-tRNA synthetase (SerRS) contains a 20-amino acid C-terminal extension, which is not found in prokaryotic SerRS enzymes. A truncated yeast SES1 gene, lacking the 60 base pairs that encode this C-terminal domain, is able to complement a yeast SES1 null allele strain; thus, the C-terminal extension in SerRS is dispensable for the viability of the cell. However, the removal of the C-terminal peptide affects both stability of the enzyme and its affinity for the substrates. The truncation mutant binds tRNA with 3.6-fold higher affinity, while the Km for serine is 4-fold increased relative to the wild-type SerRS. This indicates the importance of the C-terminal extension in maintaining the overall structure of SerRS.
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PMID:The C-terminal extension of yeast seryl-tRNA synthetase affects stability of the enzyme and its substrate affinity. 857 7

Like all other eukaryal cytosolic seryl-tRNA synthetase (SerRS) enzymes, Saccharomyces cerevisiae SerRS contains a C-terminal extension not found in the enzymes of eubacterial and archaeal origin. Overexpression of C-terminally truncated SerRS lacking the 20-amino acid appended domain (SerRSC20) is toxic to S. cerevisiae possibly because of altered substrate recognition. Compared to wild-type SerRS the truncated enzyme displays impaired tRNA-dependent serine recognition and is less stable. This suggests that the C-terminal peptide is important for the formation or maintenance of the enzyme structure optimal for substrate binding and catalysis.
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PMID:C-terminal truncation of yeast SerRS is toxic for Saccharomyces cerevisiae due to altered mechanism of substrate recognition. 984 29

The genomic sequences of Methanococcus jannaschii and Methanobacterium thermoautotrophicum contain a structurally uncommon seryl-tRNA synthetase (SerRS) sequence and lack an open reading frame (ORF) for the canonical cysteinyl-tRNA synthetase (CysRS). Therefore, it is not clear if Cys-tRNACys is formed by direct aminoacylation or by a transformation of serine misacylated to tRNACys. To address this question, we prepared SerRS from two methanogenic archaea and measured the enzymatic properties of these proteins. SerRS was purified from M. thermoautotrophicum; its N-terminal peptide sequence matched the sequence deduced from the relevant ORF in the genomic data of M. thermoautotrophicum and M. jannaschii. In addition, SerRS was expressed from a cloned Methanococcus maripaludis serS gene. The two enzymes charged serine to their homologous tRNAs and also accepted Escherichia coli tRNA as substrate for aminoacylation. Gel shift experiments showed that M. thermoautotrophicum SerRS did not mischarge tRNACys with serine. This indicates that Cys-tRNACys is formed by direct acylation in these organisms.
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PMID:Sequence divergence of seryl-tRNA synthetases in archaea. 985 85

In previous studies it has been shown that neural cells undergoing programmed cell death display strongly positive cytoplasmic immunoreactivity to polyclonal antibodies directed against a c-Jun N-terminal peptide. It was later found that c-Jun-like immunoreactivity in apoptosis was due to cross-reactivity with proteins other than c-JUN: We have analysed the biochemical counterpart of this property in neuroblastoma cell lines treated to induce apoptosis. Using the c-Jun/sc-45 antibody, several bands with apparent molecular masses distinct from c-Jun were detected in extracts in parallel with both the degree of apoptosis and the appearance of the cytoplasmic signal after immunostaining. c-Jun/sc-45 immunostaining was prevented by caspase inhibitors and did not require de novo protein synthesis. One of the antigens recognized by the c-Jun/sc-45 antibody was identified as seryl-tRNA synthetase. We provide evidence that seryl-tRNA synthetase is a substrate of caspase-3 in vitro and that the digested form turns highly immunoreactive towards the antibody. A carboxy-terminus epitope of the protein that constitutes a consensus site for caspase-3 is involved in c-Jun/sc-45 recognition. This epitope shares some amino acids with the peptide used as the immunogen and this could explain the cross-reactivity observed. In conclusion, we demonstrate here that cytoplasmic c-Jun/sc-45-like immunoreactivity specific to apoptosis is due to post-translational changes which occur in seryl-tRNA synthetase and probably also in other proteins as a consequence of caspase mediated proteolysis.
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PMID:Antibodies against c-Jun N-terminal peptide cross-react with neo-epitopes emerging after caspase-mediated proteolysis during apoptosis. 1133 19