Novel complex formed between a nonproteolytic cell wall protein of group A streptococci and alpha 2-macroglobulin

Chhatwal, Gursharan S.; Albohn, Gudrun; Blobel, H.

doi:10.1128/jb.169.8.3691-3695.1987

Cited by 21 publications

(15 citation statements)

References 35 publications

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“…Protein GRAB is the only ␣ 2 M-binding surface protein expressed by KTL3 bacteria and the S. pyogenes ␣ 2 M-binding protein reported by Chhatwal et al (10) is larger than protein GRAB (78 kDa as compared with 23 kDa). The mode of interaction between protein GRAB and ␣ 2 M is also different from that of the 78-kDa protein and ␣ 2 M. When bound to the 78-kDa protein, ␣ 2 M was reported to be converted to a non-native form (10). This is in contrast to the ␣ 2 M bound to KTL3 cells via protein GRAB.…”

Section: Discussioncontrasting

confidence: 40%

“…The binding of native ␣ 2 M to group C and G streptococci has been attributed to protein G (11,12), a surface-associated molecule with separate binding sites also for human IgG and human serum albumin (35)(36)(37). An ␣ 2 M-binding surface protein of 78 kDa from group A streptococci has also been described, but the sequence of this protein is not known (10). In the present work a novel ␣ 2 M-binding protein in S. pyogenes is identified and characterized.…”

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confidence: 99%

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Protein GRAB of Streptococcus pyogenes Regulates Proteolysis at the Bacterial Surface by Binding α2-Macroglobulin

Rasmussen

Müller²,

Björck

1999

Journal of Biological Chemistry

124

123

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In the molecular interplay between pathogenic microorganisms and their host, proteolytic mechanisms are believed to play a crucial role. Here we find that the important human pathogen Streptococcus pyogenes (group A Streptococcus) expresses a surface protein with high affinity (K a ‫؍‬ 2.0 ؋ 10 8 M ؊1 ) for ␣ 2 -macroglobulin (␣ 2 M), the dominating proteinase inhibitor of human plasma. The immunoglobulin-binding protein G of group C and G streptococci also contains an ␣ 2 M-binding domain and a gene encoding protein GRAB (protein G-related ␣ 2 M-binding protein) was identified in the S. pyogenes Genome Sequencing data base. The grab gene is present in most S. pyogenes strains and is well conserved. Protein GRAB has typical features of a surfaceattached protein of Gram-positive bacteria. It also contains a region homologous to parts of the ␣ 2 M-binding domain of protein G and a variable number of a unique 28-amino acid-long repeat. Using Escherichia coli-produced protein GRAB and synthetic GRAB peptides, the ␣ 2 M-binding region was mapped to the NH 2 -terminal part of protein GRAB, which is the region with homology to protein G. An isogenic S. pyogenes mutant lacking surface-associated protein GRAB showed no ␣ 2 M binding activity and was attenuated in virulence when injected intraperitoneally in mice. Finally, ␣ 2 M bound to the bacterial surface via protein GRAB was found to entrap and inhibit the activity of both S. pyogenes and host proteinases, thereby protecting important virulence determinants from proteolytic degradation. This regulation of proteolytic activity at the bacterial surface should affect the host-microbe relation during S. pyogenes infections.Streptococcus pyogenes is an important human pathogen that causes a variety of diseases such as pharyngitis, impetigo, scarlatina, and erysipelas. More severe infections caused by this organism are necrotizing fasciitis and streptococcal toxic shock-like syndrome. S. pyogenes binds several human plasma proteins via its surface proteins. The surface proteins studied in most detail are the M or M-like proteins, which are responsible for the ability of S. pyogenes to resist phagocytosis (1, 2).M proteins bind several human plasma proteins like fibrinogen (3), IgG (4, 5), and regulatory proteins of the complement system (6, 7). The binding activities of M proteins have been proposed to be of importance for the antiphagocytic activity of these proteins (2, 6 -9).Several different streptococcal species also bind ␣ 2 M 1 (10 -16), which is an abundant homotetrameric plasma protein of 718 kDa best characterized as a proteinase inhibitor (17). During infection proteinases are released both by bacteria and damaged host cells, and tight regulation of proteolytic activity is thus essential. S. pyogenes secretes a cysteine proteinase (SCP), which has several important functions and is regarded as a major virulence factor of this bacterium (18 -25). There is no described inhibitor of the SCP even though it is known that essentially all proteinases from the four clas...

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Section: Discussioncontrasting

confidence: 40%

mentioning

confidence: 99%

Protein GRAB of Streptococcus pyogenes Regulates Proteolysis at the Bacterial Surface by Binding α2-Macroglobulin

Rasmussen

Müller²,

Björck

1999

Journal of Biological Chemistry

124

123

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“…Plasma protein binding sites of streptococci could play an important role in streptococcal pathogenicity, since they might be involved in crucial mechanisms of the host defense [14]. Human and animal pathogenic streptococci are able to facilitate their adherence to host cells by binding of fibronectin [15,16] and non-immune binding of IgG probably leads to inhibition of binding to specific antibodies [17]. Interaction of certain streptococci with fibrinogen enables them to resist phagocytosis [18].…”

Section: Discussionmentioning

confidence: 99%

Role of α2-macroglobulin in phagocytosis of group A and C streptococci

Valentin‐Weigand

Traore

Blobel

et al. 1990

FEMS Microbiology Letters

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Binding of alpha 2-macroglobulin (alpha 2M) to streptococci and its effects on phagocytosis were investigated. Two types of streptococcal binding sites for alpha 2M were observed: Streptococcus pyogenes from human infections interacted only with native alpha 2M whereas S. dysgalactiae from bovine and S. equi from equine infections bound only a complex of alpha 2M with trypsin (alpha 2M-T). Preincubation of S. pyogenes with native alpha 2M substantially enhanced their phagocytosis by human polymorphonuclear neutrophils (PMN) whereas preincubation with alpha 2M-T was without any effect. On the other hand, incubation of S. dysgalactiae and S. equi with alpha 2M-T markedly reduced their phagocytosis by PMN from the respective host species. Native alpha 2M did not affect the phagocytosis of these streptococci. Digestion of the streptococcal binding sites for alpha 2M and alpha 2M-T pronase abolished the enhancement of phagocytosis of S. pyogenes by native alpha 2M as well as the inhibition of phagocytosis of S. dysgalactiae and S. equi by alpha 2M-T. Thus, binding of alpha 2M or its complexes appeared to play a role in streptococcal pathogenicity.

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“…Binding experiments. Cells of streptococcal cultures were harvested by centrifugation, washed twice with PBS, and suspended in PBS containing 0.1% Tween 20 to give 10% transmission at 600 nm (8,10). Then 200 ,ul of the cell suspension was added to 10 ng of 125I-labeled fibronectin (specific activity, 2.91 mCi/mg) which had been incubated for 5 min with either 20-,ul quantities of increasing concentrations (0.05 to 2.5 mg of total protein per ml) of lysate from E. coli overexpressing Sfb fusion protein or 50-,ul quantities (2.5 to 100 ,ug/ml) of purified fusion protein.…”

Section: Methodsmentioning

confidence: 99%

Fibronectin-binding protein of Streptococcus pyogenes: sequence of the binding domain involved in adherence of streptococci to epithelial cells

Talay¹,

Valentin‐Weigand²,

Jerlström³

et al. 1992

Infect Immun

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211

118

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The sequence of the fibronectin-binding domain of the fibronectin-binding protein of Streptococcus pyogenes (Sfb protein) was determined, and its role in streptococcal adherence was investigated by use of an Sfb fusion protein in adherence studies. A 1-kb DNA fragment coding for the binding domain of Sfb protein was cloned into the expression vector pEX31 to produce an Sfb fusion protein consisting of the N-terminal part of MS2 polymerase and a C-terminal fragment of the streptococcal protein. Induction of the vector promoter resulted in hyperexpression of fibronectin-binding fusion protein in the cytoplasm of the recombinant Escherichia coli cells. Sequence determination of the cloned 1-kb fragment revealed an in-frame reading frame for a 268-amino-acid peptide composed of a 37-amino-acid sequence which is completely repeated three times and incompletely repeated a fourth time. Cloning of one repeat into pEX31 resulted in expression of small fusion peptides that show fibronectin-binding activity, indicating that one repeat contains at least one binding domain.Each repeat exhibits two charged domains and shows high homology with the 38-amino-acid D3 repeat of the fibronectin-binding protein of Staphylococcus aureus. Sequence comparison with other streptococcal ligandbinding surface proteins, including M protein, failed to reveal significant homology, which suggests that Sfb protein represents a novel type of functional protein in S. pyogenes. The Sfb fusion protein isolated from the cytoplasm of recombinant cells was purified by fast protein liquid chromatography. It showed a strong competitive inhibition of fibronectin binding to S. pyogenes and of the adherence of bacteria to cultured epithelial cells. In contrast, purified streptococcal lipoteichoic acid showed only a weak inhibition of fibronectin binding and streptococcal adherence. These results demonstrate that Sfb protein is directly involved in the fibronectin-mediated adherence of S. pyogenes to epithelial cells.

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Novel complex formed between a nonproteolytic cell wall protein of group A streptococci and alpha 2-macroglobulin

Cited by 21 publications

References 35 publications

Protein GRAB of Streptococcus pyogenes Regulates Proteolysis at the Bacterial Surface by Binding α2-Macroglobulin

Protein GRAB of Streptococcus pyogenes Regulates Proteolysis at the Bacterial Surface by Binding α2-Macroglobulin

Role of α2-macroglobulin in phagocytosis of group A and C streptococci

Fibronectin-binding protein of Streptococcus pyogenes: sequence of the binding domain involved in adherence of streptococci to epithelial cells

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