* If you want to update the article please login/register
Alzheimer's disease's brain is vulnerable to oxidative damage by reactive oxygen species that may cause methionine oxidation. Oxidation of the sole methionine of beta-amyloid phosphate and possibly methionine residues of other extracellular proteins may be one of the first events contributing to A and other proteins' toxicity in vivo. We immunized transgenic AD mice at 4 months of age with a recombinant methionine sulfoxide-rich protein from Zea cans in the current research. These results from a preclinical AD model are likely translational, showing that active immunization can reduce or prevent AD onset.
Source link: https://doi.org/10.3390/antiox11040775
These results show that plants respond to virulent pathogens by producing active oxygen species, and that enzymes that repair oxidative damage enable virulent pathogens to survive in the host environment, supporting the belief that active oxygen species play a vital role in plant defense.
Source link: https://doi.org/10.1073/pnas.96.3.887
Metazoine sulfoxide reductase converts some proteins inactivation due to oxidation of vital methionine residues by reducing Metthionine sulfoxide, Met, to methionine. MsrA's production is independent of bound metal and cofactors, but it does require reducing equivalents from either DTT or a thioredoxin-regeneration unit. The four cysteine residues of bovine MsrA were mutated to serine in a series of permutations in an attempt to interpret these findings. These residues shuttled reducing equivalents of thioredoxin to the active site in the absence of thioredoxin, according to the dramatically reduced activity of the Cys-218 and Cys-227 variants in the presence of thioredoxin. A reaction scheme was developed based on the existing MsrA data and a reaction mechanism based on reactivities of thiols with sulfoxides. Cys-72 appears as a nucleophile and assaults the sulfur atom of the sulfoxide moiety, resulting in the formation of a covalent, tetracoordinate intermediate in this scheme.
Source link: https://doi.org/10.1073/pnas.97.12.6463
By using a high-copy plasmid harboring the msrA gene and its promoter, a yeast peptide-sulfoxide reductase was overexpressed in a Saccharomyces cerevisiae null mutant of msrA. The oxidation of free methionine in a medium lacking hydrogen peroxide had no effect on the growth pattern, suggesting that free methionine oxidation in the growth medium was not the primary reason for growth inhibition of the msrA mutant. In human T lymphocyte cells that were stably transfected with the bovine msrA and exposed to hydrogen peroxide, an enhanced resistance to hydrogen peroxide therapy was demonstrated. When grown in the presence of hydrogen peroxide, the transfected strain's survival rate was much higher than its parent strain when grown in the absence of hydrogen perfected.
Source link: https://doi.org/10.1073/pnas.95.24.14071
Peptide methionine sulfoxide residues in proteins as well as in a large number of methyl sulfoxide compounds. MsrA was found in various rat tissues by using immunocytochemical staining. The msrA gene was mapped to mouse chromosome 14 in a region of homology with human chromosomes 13 and 8p21.
Source link: https://doi.org/10.1073/pnas.93.8.3205
E. coli msrA cDNA homologue encodes a protein of 255 amino acids with a calculated molecular mass of 25,846 Da. MsrA's mammalian recombinant MsrA can be used as substrate, proteins containing Met, as well as other organic compounds containing an alkyl sulfoxide group, such as N-acetylMet, Met, and dimethyl sulfoxide. mRNA from rats msrA mRNA was found in a variety of organs, with the highest concentration in kidney found in kidneys, according to a Northern analysis of rat tissue extracts.
Source link: https://doi.org/10.1073/pnas.93.5.2095
In chromosome V of Saccharomyces cerevisiae, a gene homologous to methionine sulfoxide reductase was identified as the predicted ORF, encoding a protein containing 184 amino acids. MsrA recombinant yeast had the same substrate specificity as other well-known MsrA enzymes from mammalian and bacterial cells. In addition, high amounts of free and protein-bound methionine sulfoxide were discovered in extracts of msrA mutant cells related to their wild-type parent cells under various oxidative stress. MsrA's ability to restore oxidative damage in vivo could be of utmost importance if methionine residues function as antioxidants.
Source link: https://doi.org/10.1073/pnas.94.18.9585
A screen of a library of pneumococcal mutants for loss of adherence revealed a MsrA mutant with 75% reduced binding to GalNAcbeta1-4Gal that is present on type II lung cells and vascular endothelial cells. An E. coli msrA mutant was found to have reduced type I fimbriae-mediated, mannose-dependent agglutination of erythrocytes. Mutants with defects in the pilA-pilB locus from N. gonorrhoeae, according to 4367-4378, were modified in their manufacture of type IV pili mutants. MsrA and gonococcal PilB expressed in E. coli have MsrA activity, as shown by our analysis.
Source link: https://doi.org/10.1073/pnas.93.15.7985
Protein oxidation by reactive oxygen species is associated with aging, oxidative stress, and several diseases. These oxidations are quickly remedied by methionine sulfoxide derivative oxidation, which can be easily remedied by methionine sulfoxide reductase's action. We have created a strain of mouse that lacks the MsrA gene in order to get a better understanding of MsrA's metabolic functions. MsrA, therefore, appears that it may play a vital role in aging and neurological disorders.
Source link: https://doi.org/10.1073/pnas.231472998
The reactive nitrogen intermediates nitrite and S-nitrosoglutathione, which are bactericidal in vitro, are bactericidal in vitro and are characteristic of activated macrophages' phagosome in vitro. Peptide methionine sulfoxide reductase reduces protein methionine reductase to methionine, which can be traced back to methionine sulfoxide reductase. The classic phenotype was revived by transformation with plasmids encoding msrA from E. coli or M. tuberculosis, but not by an enzymatically inactive mutant msrA, indicating that Met oxidation was involved in the death of these cells. When these RNI cannot properly oxidize Met, it seemed odd that nitrite and GSNO kill bacteria by oxidizing Met residues. The results are consistent with the hypotheses that nitrite and GSNO kill E. coli by intracellular conversion to peroxynitrite, that intracellular Met residues in proteins are a critical target for peroxynitrite degradation, and that MsrA can be a crucial component in the repair of peroxynitrite-mediated intracellular damage.
Source link: https://doi.org/10.1073/pnas.161295398
* Please keep in mind that all text is summarized by machine, we do not bear any responsibility, and you should always check original source before taking any actions