Disease relevance of Sepx1

• A high-molecular-mass surface protein (Lsp) and methionine sulfoxide reductase B (MsrB) contribute to the ecological performance of Lactobacillus reuteri in the murine gut [1].
• The enzyme was partially purified from mouse liver and a derivative of the mouse MsrB gene, in which the codon specifying selenocystein incorporation was replaced by the cystein codon, was prepared, cloned, and overexpressed in Escherichia coli [2].
• Also, we have shown that in Staphylococcus aureus there are two MsrA and one nonselenoprotein MsrB, which demonstrates the same substrate stereospecificity as the mouse MsrB [2].

High impact information on Sepx1

• Selenium-deficient diet enhances protein oxidation and affects methionine sulfoxide reductase (MsrB) protein level in certain mouse tissues [3].
• Here we report that cysteine homologs of SelR are present in all organisms except certain parasites and hyperthermophiles, and this pattern of occurrence closely matches that of only one protein, peptide methionine sulfoxide reductase (MsrA) [4].
• Moreover, in several genomes, SelR and MsrA genes are fused or clustered, and their expression patterns suggest a role of both proteins in protection against oxidative stress [4].
• We found that human and mouse genomes possess three MsrB genes and characterized their protein products, designated MsrB1, MsrB2, and MsrB3 [5].
• MsrB1 (Selenoprotein R) was present in the cytosol and nucleus and exhibited the highest methionine-R-sulfoxide reductase activity because of the presence of selenocysteine (Sec) in its active site [5].

Anatomical context of Sepx1

• Characterization of mouse endoplasmic reticulum methionine-R-sulfoxide reductase [6].

Associations of Sepx1 with chemical compounds

• These findings identify a function of the conserved SelR enzyme family, define a pathway of methionine sulfoxide reduction, reveal a case of convergent evolution of similar function in structurally distinct enzymes, and suggest a previously uncharacterized redox regulatory role of selenium in mammals [4].
• Selenoprotein R is a zinc-containing stereo-specific methionine sulfoxide reductase [4].
• Liver and kidney of the MsrB1 knock-out mice also showed increased levels of malondialdehyde, protein carbonyls, protein methionine sulfoxide, and oxidized glutathione as well as reduced levels of free and protein thiols, whereas these parameters were little changed in other organs examined [7].

Other interactions of Sepx1

• When SECISearch was applied to search human dbEST, two new mammalian selenoproteins, designated SelT and SelR, were identified [8].

References