Dataset Information

The role of cysteine-150 in the structure and activity of rat liver S-adenosyl-L-methionine synthetase.

ABSTRACT: The present paper reports the tryptic digestion of N-ethylmaleimide-treated S-adenosyl-L-methionine synthetase (high- and low-Mr forms) and the isolation of the modified peptides by h.p.l.c. There is only one site modified after 5 min incubation, and the modification at this site correlates with the main activity decrease. The amino acid composition of this peptide was determined, and its localization in the sequence shows the modified residue as cysteine-150, which is located close to the putative ATP-binding site. Modification of the enzyme for 20 min led to the appearance of a second labelled peptide, which seems to be responsible for about a further 10% of the activity loss. The modification by N-ethylmaleimide of the enzyme was partially prevented in the presence of adenosine 5'-[beta gamma-imido]triphosphate and methionine, further supporting the hypothesis that the modified residues lie within the active site. Urea treatment of the enzyme, followed by modification with N-ethylmaleimide, produces the modification of 7 of the 10 cysteine residues present in the sequence. The results obtained were the same for either of the isoforms.

SUBMITTER: Pajares MA

PROVIDER: S-EPMC1150192 | biostudies-other | 1991 Feb

REPOSITORIES: biostudies-other

ACCESS DATA

Similar Datasets

Project description:Methionine adenosyl transferases (MATs) catalyze the synthesis of the biological methyl donor adenosylmethionine (SAM). Dysregulation of MATs has been associated with carcinogenesis in humans. We previously found that downregulation of the MAT1A gene enriches the protein-associated translation process and worsens liver hepatocellular carcinoma (LIHC) prognosis. We also discovered that subcellular localization of the MAT2A protein has independently prognostic relevance in breast cancer patients. The present study aimed to examined the clinical relevance of MAT2A translocation in human LIHC. Essential methionine cycle gene expressions in TCGA LIHC datasets were analyzed using Gene Expression Profiling Interactive Analysis 2 (GEPIA2). The protein expression pattern of MAT2A was determined in the tissue array of our own LIHC cohort (n = 261) using immuno-histochemistry, and the prognostic relevance of MAT2A protein's subcellular localization expression was examined using Kaplan-Meier survival curves. LIHC patients with higher MAT2A mRNA expression had a worse survival rate (p = 0.0083). MAT2A protein immunoreactivity was observed in both cytoplasm and nucleus fractions in the tissue array. Tumor tissues had elevated MAT2A protein expression in both cytoplasm and nucleus compared to their adjacent normal tissues. A higher cytoplasmic to nuclear MAT2A protein expression ratio (C/N) was found in female LIHC patients compared to that of male patients (p = 0.047). Kaplan-Meier survival curves showed that a lower MAT2A C/N correlated with poor overall survival in female LIHC patients (10-year survival rate: 29.2% vs. 68.8%, C/N ≤ 1.0 vs. C/N > 1.0, log-rank p = 0.004). Moreover, we found that specificity protein 1 (SP1) may have a potential interaction with nuclear MAT2A protein, using protein-protein interaction; this we found using the GeneMANIA algorithm. We explored the possible protective effects of the estrogen axis in LIHC using the Human Protein Atlas (HPA), and found evidence supporting a possible protective effect of estrogen-related protein ESSRG in LIHC. The localization of SP1 and MAT2 appeared to be inversely associated with ESRRG expression in LIHC. The present study demonstrated the translocation of MAT2A and its prognostic relevance in female LIHC patients. Our findings suggest the potential of estrogen in SP1 regulation and localization of MAT2A, as therapeutic modalities against in female LIHC patients.

Dataset Information

The role of cysteine-150 in the structure and activity of rat liver S-adenosyl-L-methionine synthetase.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets