Selenocysteine (Sec) is incorporated into proteins in response to UGA codons. This residue is frequently found at the catalytic sites of oxidoreductases. In this study, we characterized the selenoproteome of an anaerobic bacterium, Clostridium sp. (also known as Alkaliphilus oremlandii) OhILA, and identified 13 selenoprotein genes, five of which have not been previously described. One of the de...

Selenium is a chemical element participating in the synthesis of selenocysteine residues that play a pivotal role in the enzymatic activity efficiency of selenoproteines. The methionine sulfoxide reductase (Msr) system that reduces methionine sulfoxide (MetO) to methionine comprises the selenoprotein MsrB (MsrB1) and the non-selenoprotein MsrA, which reduce the R- and the S- forms of MetO, resp...

Methionine (Met) sulfoxide reductase A (MsrA) is a key endogenous antioxidative enzyme with longevity benefits in animals. Only very few approaches have been reported to enhance MsrA function. Recent reports have indicated that the antioxidant capability of MsrA may involve a Met oxidase activity that facilities the reaction of Met with reactive oxygen species (ROS). Herein, we used a homology ...

Seventy-eight isolates of different Enterococcus species (E. faecalis, n = 27; E. faecium, n = 23; E. durans, n = 8; E. avium, n = 6; E. hirae, n = 9; E. gallinarum, n = 3; and E. casseliflavus, n = 2) with a variety of erythromycin resistance phenotypes were examined for the presence of macrolide resistance genes (ermA, ermB, ermC, ermTR, mefA/E, and msrA). Positive PCR amplifications of ermB ...

In proteins, methionine residues are primary targets for oxidation. Methionine oxidation is reversed by methionine sulfoxide reductases A and B, a class of highly conserved enzymes. Ffh protein, a component of the ubiquitous signal recognition particle, contains a methionine-rich domain, interacting with a small 4.5S RNA. In vitro analyses reported here show that: (i) oxidized Ffh is unable to ...

Oxidation of proteins by reactive oxygen species is associated with aging, oxidative stress, and many diseases. Although free and protein-bound methionine residues are particularly sensitive to oxidation to methionine sulfoxide derivatives, these oxidations are readily repaired by the action of methionine sulfoxide reductase (MsrA). To gain a better understanding of the biological roles of MsrA...

Meconium ileus (MI), a life-threatening intestinal obstruction due to meconium with abnormal protein content, occurs in approximately 15 percent of neonates with cystic fibrosis (CF). Analysis of twins with CF demonstrates that MI is a highly heritable trait, indicating that genetic modifiers are largely responsible for this complication. Here, we performed regional family-based association ana...

The microaerophilic food-borne pathogen Campylobacter jejuni is exposed to highly variable oxygen concentrations during its life cycle and employs a variety of protection mechanisms to resist oxidative stress. However, not all of the enzymes that mediate such protection have yet been identified. Two genes in strain NCTC 11168, Cj0637c and Cj1112c, are predicted to encode unrelated methionine su...

Considering the importance of inflammation and apoptosis in neurodegenerative conditions, the potential suppressive effects of the Rg3, a by-product obtained during the steaming of red ginseng, may indicate that Rg3 could provide a beneficial therapeutic approach to treating or preventing neurodegenerative disease. We investigated the effect of Rg3 on Abeta42-mediated microglial activation and ...

The enzyme peptide methionine sulfoxide reductase (MsrA), the product of the msrA gene, catalyzes the reduction of methionine sulfoxide residues in proteins to methionine (1, 3, 4). During aerobic metabolism, methionine in proteins may be oxidized to methionine sulfoxide by biological reagents such as hydrogen peroxide, hydroxyl radicals, and hypochlorite and superoxide ions (reviewed in refere...