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Ulrich von Pawel-Rammingen

Publications and source records attributed to Ulrich von Pawel-Rammingen.

9 recordsLinked to original sources
PubMed2006

IdeS, a highly specific immunoglobulin G (IgG)-cleaving enzyme from Streptococcus pyogenes, is inhibited by specific IgG antibodies generated during infection.

IdeS, a recently discovered cysteine proteinase secreted by the important human pathogen Streptococcus pyogenes, interferes with phagocytic killing by specifically cleaving the heavy chain of immunoglobulin G. The fact that the enzyme targets one of the key molecules of the adapted immune response raised the question of whether an antibody response against IdeS could inhibit, i.e., neutralize, enzyme activity. Paired acute- and convalescent-phase serum samples from patients with pharyngotonsillitis (n = 10), bacteremia (n = 7), and erysipelas (n = 4) were analyzed. Antibodies with the ability to neutralize IdeS enzymatic activity were already found in two-thirds of acute-phase sera. However, patients who seroconverted to IdeS, in particular patients with pharyngotonsillitis and erysipelas, developed specific antibodies during convalescence with an increased capability to efficiently neutralize the enzymatic activity of IdeS. Also, the presence of neutralizing antibodies decreased the ability of IdeS to mediate bacterial survival in human immune blood. In patients with bacteremia, several acute-phase sera contained neutralizing antibodies, but no correlation was found to severity or outcome of invasive infections. Still, the fact that the human immune response targets the enzymatic activity of IdeS supports the view that the enzyme plays an important role during streptococcal infection.

Amino Acid Sequence↗
PubMed2004

Enzymatic characterization of the streptococcal endopeptidase, IdeS, reveals that it is a cysteine protease with strict specificity for IgG cleavage due to exosite binding.

Streptococcus pyogenes, an important pathogen in humans, secretes an IgG specific endopeptidase named IdeS. To elucidate the mechanism that is responsible for this specificity, we have here characterized the activity of IdeS in detail. Both gamma chains of human IgG or its Fc fragment were cleaved in the hinge region after Gly236 by IdeS, but other proteins or synthetic peptides containing sequences such as the P(4)-P(1) segment in the IgG cleavage site, or long peptides resembling the IgG hinge, were not hydrolyzed at all. This is likely due to a second binding site interacting with the Fc part of IgG. The lack of IdeS activity on peptide substrates necessitated the development of an assay with IgG as the substrate for kinetic studies. IdeS showed a sigmoidal velocity curve at physiological IgG concentrations, and a declining enzyme rate at higher IgG concentrations. This atypical velocity curve suggests product inhibition and/or allosteric control, which again indicates the presence of an exosite involved in substrate binding. The pseudoequilibrium constant for IdeS hydrolysis of IgG was 90 microM. The enzyme exhibited activity in the pH range of 5.1-7.6, with an optimum at pH 6.6. IdeS was stable above pH 10 but not at acidic pH. It exhibited an activity maximum around 37 degrees C and a decreased thermal stability at 42 degrees C. Iodoacetate and iodoacetamide inhibited IdeS, as expected for a cysteine protease, and biochemical evidence verified this classification. E-64 and chicken cystatin, specific inhibitors of family C1 and C13 cysteine proteases, were without effect on enzyme activity, as were class specific serine, aspartic, and metallo protease inhibitors. No significant similarities were found in protein sequence comparisons with known enzyme families, suggesting that IdeS represents a novel family of cysteine proteases.

Amino Acid Sequence↗
PubMed2004

Structure of the streptococcal endopeptidase IdeS, a cysteine proteinase with strict specificity for IgG.

Pathogenic bacteria have developed complex and diverse virulence mechanisms that weaken or disable the host immune defense system. IdeS (IgG-degrading enzyme of Streptococcus pyogenes) is a secreted cysteine endopeptidase from the human pathogen S. pyogenes with an extraordinarily high degree of substrate specificity, catalyzing a single proteolytic cleavage at the lower hinge of human IgG. This proteolytic degradation promotes inhibition of opsonophagocytosis and interferes with the killing of group A Streptococcus. We have determined the crystal structure of the catalytically inactive mutant IdeS-C94S by x-ray crystallography at 1.9-A resolution. Despite negligible sequence homology to known proteinases, the core of the structure resembles the canonical papain fold although with major insertions and a distinct substrate-binding site. Therefore IdeS belongs to a unique family within the CA clan of cysteine proteinases. Based on analogy with inhibitor complexes of papain-like proteinases, we propose a model for substrate binding by IdeS.

Amino Acid Sequence↗
PubMed2004

Low antibody levels against cell wall-attached proteins of Streptococcus pyogenes predispose for severe invasive disease.

Acute-phase serum samples from 70 patients with group A streptococcal (GAS) invasive disease were analyzed for IgG antibodies against 6 recently characterized GAS virulence factors (SclA, SclB, GRAB, MtsA, EndoS, and IdeS) and SpeB. Antibody levels against the cell wall-attached GAS antigens SclA, SclB, and GRAB were significantly lower in patients with severe invasive disease (streptococcal toxic shock syndrome [STSS] and/or necrotizing fasciitis [NF]; n=35), compared with levels in patients with nonsevere GAS bacteremia (n=35). Among patients with severe invasive disease, significantly lower antibody levels against GRAB were found in patients with STSS (n=10) than in patients with NF (n=17). Antibody levels against SpeB in patients with severe bacteremia were similar to those in patients with nonsevere bacteremia, and levels in patients with STSS were similar to those in patients with NF. The data indicate that immunity to cell wall-attached proteins may play a role in the protection against severe invasive disease and that antibodies against GRAB may be of importance in the pathogenesis of STSS.

Antibodies, Bacterial↗
PubMed2004

SpeB modulates fibronectin-dependent internalization of Streptococcus pyogenes by efficient proteolysis of cell-wall-anchored protein F1.

SpeB is a cysteine proteinase and virulence determinant secreted by the important human pathogen Streptococcus pyogenes. Recent investigations have suggested a role for SpeB in streptococcal entry into human cells. However, conflicting data concerning the contribution of SpeB to internalization have been presented. Protein F1 is a cell-wall-attached fibronectin (Fn)-binding protein that is present in a majority of streptococcal isolates and is important for internalization. This study shows that protein F1 is efficiently degraded by SpeB, and that removal of protein F1 from the bacterial surface leads to reduced internalization. Whereas M1 protein and protein H, two additional surface proteins of S. pyogenes that bind human plasma proteins, are protected from proteolytic degradation by their ligands, protein F1 is readily cleaved by SpeB also when in complex with Fn. This finding, and the connection between the presence of Fn at the bacterial surface and entry into human cells, suggest that SpeB plays a role in the regulation of the internalization process.

Adhesins, Bacterial↗
PubMed2003

IdeS and SpeB: immunoglobulin-degrading cysteine proteinases of Streptococcus pyogenes.

The Gram-positive bacterium Streptococcus pyogenes is a major human pathogen causing substantial morbidity and mortality in society. S. pyogenes has evolved numerous molecular mechanisms to avoid the various actions of the human immune system and has established means to modulate both adaptive and innate immune responses. S. pyogenes produces and secretes proteolytic enzymes, which have an important impact on the ability of the bacteria to survive in the human host. Prominent among these are two immunoglobulin-degrading enzymes: the newly discovered streptococcal cysteine proteinase, IdeS, and the classical cysteine proteinase of S. pyogenes, SpeB.

Antibodies, Bacterial↗
PubMed2002

IdeS, a novel streptococcal cysteine proteinase with unique specificity for immunoglobulin G.

Recent work from several laboratories has demonstrated that proteolytic mechanisms significantly contribute to the molecular interplay between Streptococcus pyogenes, an important human pathogen, and its host. Here we describe the identification, purification and characterization of a novel extracellular cysteine proteinase produced by S.pyogenes. This enzyme, designated IdeS for Immunoglobulin G-degrading enzyme of S.pyogenes, is distinct from the well-characterized streptococcal cysteine proteinase, SpeB, and cleaves human IgG in the hinge region with a high degree of specificity. Thus, other human proteins, including immunoglobulins M, A, D and E, are not degraded by IdeS. The enzyme efficiently cleaves IgG antibodies bound to streptococcal surface structures, thereby inhibiting the killing of S.pyogenes by phagocytic cells. This and additional observations on the distribution and expression of the ideS gene indicate that IdeS represents a novel and significant bacterial virulence determinant, and a potential therapeutic target.

Amino Acid Sequence↗
PubMedDate not supplied

The protein expression of Streptococcus pyogenes is significantly influenced by human plasma.

During the course of infection, the common human pathogen Streptococcus pyogenes encounters plasma. We show that plasma causes S. pyogenes to rapidly remodel its cellular metabolism and virulence pathways. We also identified a variant of the major virulence factor, M1 protein, lacking 13 amino acids at the NH(2)-terminus in bacteria grown with plasma. The pronounced effect of plasma on protein expression, suggests this is an important adaptive mechanism with implications for S. pyogenes pathogenicity.

Amino Acids↗