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Toxin-antitoxin systems were shown to be involved in plasmid maintenance when they were initially discovered, but other roles have been demonstrated since. Here we identify and characterize a novel toxin-antitoxin system (pemIKSa) located on Staphylococcus aureus plasmid pCH91. The toxin (PemKSa) is a sequence-specific endoribonuclease recognizing the(More)
The aim of this study was to reveal potential markers associated with drug dependence, using the proteomic approach. Gels containing samples derived from morphine-treated and control animals were compared and analyzed. Inspection of protein profiles, following TCA/acetone precipitation and the use of nano-scale liquid chromatography coupled to tandem mass(More)
Porphyromonas gingivalis possesses a complex proteolytic system, which is essential for both its growth and evasion of host defense mechanisms. In this report we characterized, both at a protein and genomic level, a novel peptidase of this system with prolyl tripeptidyl peptidase activity. The enzyme was purified to homogeneity, and its enzymatic activity(More)
We report the complete coding sequence and the partial amino acid sequence (determined by chemical sequencing) of Staphylococcus epidermidis extracellular cysteine (Ecp) and serine (Esp) proteases. The first enzyme shows an extended sequence similarity to Staphylococcus aureus cysteine protease (staphopain) and the second one resembles the serine protease(More)
Deprived of heme and partially unfolded hemoglobin, myoglobin and cytochrome c display microbicidal activity against a broad spectrum of microorganisms with half maximal lethal dose estimated at micromolar concentrations. The intact proteins were ineffective. Antibacterial activity of these apohemoproteins was also sustained after digestion to approximately(More)
A novel type of cysteine proteinase inhibitor (SspC) has been recently recognized in Staphylococcus aureus (Massimi, I., Park, E., Rice, K., Muller-Esterl, W., Sauder, D.N., and McGavin, M.J. (2002) J Biol Chem 277: 41770-41777). In this paper we have identified homologous proteins encoded in the genome of S. aureus and other coagulase-negative(More)
Secretory leukocyte proteinase inhibitor (SLPI) is a well-established inhibitor of serine proteases such as human neutrophil elastase (HNE) and a NF-κB regulatory agent in immune cells. In this paper, we report that SLPI plays a previously uncharacterized role in regulating activation of plasmacytoid dendritic cells (pDCs). As the main source of IFN type I(More)
The negative regulation of p53, a major human tumor suppressor, by Mdm2 and Mdmx is crucial for the survival of a cell, whereas its aberrant function is a common feature of cancer.  Both Mdm proteins act through the spatial occlusion of the p53 transactivation (TA) domain and by the ubiquitination of p53, resulting in its degradation.  Two p53 homologues,(More)
Seminal plasma of teleost fish contains serine proteinase inhibitors related to those present in blood. These inhibitors can be bound to Q-Sepharose and sequentially eluted with a NaCl gradient. In the present study, using a two-step procedure, we purified (73-fold to homogeneity) and characterized the inhibitor eluted as the second fraction of antitrypsin(More)