A survey of IgA protease production among clinical isolates of Proteeae

Senior, B. W.; Albrechtsen, Merete; Kerr, Michael A.

doi:10.1099/00222615-25-1-27

Cited by 32 publications

(16 citation statements)

References 26 publications

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“…Identical results were obtained when the native P. mirabilis enzyme was used. These results agree with the results obtained by Loomes et al (47), who have reported that numerous Proteus strains secrete an EDTA-sensitive metalloprotease (58,59).…”

Section: Resultssupporting

confidence: 93%

“…The enzyme also cleaves secretory component, casein, gelatin, and BSA (47). Many of the data obtained in this study from both the native P. mirabilis metalloprotease and the E. coli recombinant enzyme agree with the findings of Loomes et al (45)(46)(47)(57)(58)(59). The relative molecular weight, divalent cation requirement, and substrate specificity are similar to those of previous reports, suggesting that the enzyme we have analyzed and whose gene we have cloned shares features with the enzyme studied by Loomes et al (47).…”

Section: Discussionsupporting

confidence: 90%

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Molecular analysis of a metalloprotease from Proteus mirabilis

1995

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Proteus mirabilis is known for its ability to differentiate from swimmer to swarmer cells, a process crucial for the pathogenesis of these bacteria during urinary tract infections. Among the many virulence factors produced during swarmer cell differentiation is an extracellular metalloprotease. A cosmid containing a large fragment of P. mirabilis chromosomal DNA was obtained by measuring protease expression in recombinant Escherichia coli. The recombinant and native enzymes were purified to over 95% homogeneity from culture supernatants by use of phenyl-Sepharose affinity chromatography and found to be identical. The activity of the 55-kDa enzyme was stimulated by divalent cations (Ca 2؉ > Mg 2؉) and inhibited by a chelator of these cations. The enzyme possesses substrate specificity for both serum and secretory forms of immunoglobulin A1 (IgA1) and IgA2 as well as IgG and, unlike classic IgA proteases, digested to completion both human and mouse IgA. Following subcloning, a 5-kb DNA fragment encoding recombinant protease activity was identified by insertional mutagenesis with Tn5. Four open reading frames were identified within this 5-kb region by limited nucleotide sequence analysis of DNA flanking the transposon. The nucleotide and deduced amino acid sequences of the metalloprotease structural gene (zapA) were obtained. Computerized homology studies revealed that the P. mirabilis metalloprotein is a member of the serralysin family of proteases and may be part of an operon comprising genes encoding an ATP-dependent ABC transporter in addition to the metalloprotease. The relevance of the metalloprotease to swarmer cell differentiation and pathogenicity is discussed.Proteus mirabilis is a bacterium that is often found in soil, water, and the intestinal tract of many mammals, including humans. This dimorphic bacterium can undergo dramatic morphological and physiological changes in response to growth on surfaces or in viscous environments. These changes are ultimately required to produce the multicellular motile behavior that is characterized by flagellum-assisted swarming motility over nutrient agar media. In the process of swarming, the bacteria differentiate from short, vegetative swimmer cells to elongated, highly flagellated forms referred to as swarmer cells. It is well established that inhibition of wild-type flagellarfilament rotation is critical in the induction of the differentiation process (3,11,49). Differentiation requires chemical signals as well as the physical signals derived from the inhibition of flagellar rotation. Glutamine is the major extracellular signal, which is sensed by a specific transduction mechanism that is independent of the cellular and nutritional amino acid uptake system (3).P. mirabilis is not a common cause of urinary tract infection (UTI) in the normal host. Surveys of uncomplicated cystitis or acute pyelonephritis show that P. mirabilis is involved in only a few cases (49). However, P. mirabilis infects a much higher proportion of patients with complicated urinary tracts, th...

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Section: Resultssupporting

confidence: 93%

Section: Discussionsupporting

confidence: 90%

Molecular analysis of a metalloprotease from Proteus mirabilis

1995

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“…mirabilis has multiple mechanisms to evade host defenses, including the extracellular metalloprotease ZapA (27,28), also referred to as an IgA protease (24,25). ZapA is expressed in many strains of P. mirabilis (24).…”

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confidence: 99%

Proteus mirabilis ZapA Metalloprotease Degrades a Broad Spectrum of Substrates, Including Antimicrobial Peptides

2004

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The 54-kDa extracellular metalloprotease ZapA is an important virulence factor of uropathogenic Proteus mirabilis. While ZapA has the ability to degrade host immunoglobulins (Igs), the dramatic attenuation of virulence in ZapA mutants suggests that this enzyme may have a broader spectrum of activity. This hypothesis was tested by in vitro assays with purified ZapA and an array of purified protein or peptide substrates. The data reveal that many proteins found in the urinary tract are substrates of ZapA proteolysis, including complement (C1q and C3), cell matrix (collagen, fibronectin, and laminin), and cytoskeletal proteins (actin and tubulin). Proteolysis of IgA and IgG was significantly enhanced by conditions that denatured the Igs. It was discovered that the antimicrobial peptides human ␤-defensin 1 (hBD1) and LL-37 are readily cleaved by the enzyme. To the best of our knowledge, this is the first report of a bacterial protease capable of cleaving hBD1, a component of the human renal tubule innate immune response. Proteolysis of hBD1 resulted in ca. six peptides, while proteolysis of LL-37 resulted in at least nine products. Matrix-assisted laser desorption ionization-time of flight mass spectrometry analysis of the molecular masses of the reaction products indicated that ZapA preferred no distinct peptide bond. The antimicrobial activity of hBD1 and LL-37 was significantly reduced following ZapA treatment, suggesting that proteolysis results in inactivation of these peptides. The data suggest that a function of ZapA during urinary tract infections is the proteolysis of antimicrobial peptides associated with the innate immune response.

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“…In 1992, Pouedras et al demonstrated that a human isolates of P. multocida capsule type D from pulmonary infection and another from genital infection, produced extracellular proteases that cleaved human IgA and IgG. As it is known that bacteria adapted to mucosal surfaces often express such enzymatic activity (Molla et al, 1988;Senior et al, 1988) it would not be surprising if more P. multocida isolates from different sources were shown in the future to produce such enzymes. One difficulty concerning the detection of these enzymes is that protease production may disappear following only a few subcultures (Pouedras et al, 1992).…”

Section: Other Enzymesmentioning

confidence: 99%