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Role of group A Streptococcus HtrA in the maturation of SpeB protease
Author(s) -
Cole Jason N.,
Aquilina John A.,
Hains Peter G.,
Henningham Anna,
Sriprakash Kadaba S.,
Caparon Michael G.,
Nizet Victor,
Kotb Malak,
Cordwell Stuart J.,
Djordjevic Steven P.,
Walker Mark J.
Publication year - 2007
Publication title -
proteomics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.26
H-Index - 167
eISSN - 1615-9861
pISSN - 1615-9853
DOI - 10.1002/pmic.200700626
Subject(s) - proteases , protease , serine protease , cysteine protease , streptococcus pyogenes , zymogen , virulence , microbiology and biotechnology , biology , western blot , streptococcus , mutant , chemistry , biochemistry , enzyme , bacteria , genetics , gene , staphylococcus aureus
The serine protease high‐temperature requirement A (HtrA) (DegP) of the human pathogen Streptococcus pyogenes (group A Streptococcus ; GAS) is localized to the ExPortal secretory microdomain and is reportedly essential for the maturation of cysteine protease streptococcal pyrogenic exotoxin B (SpeB). Here, we utilize HSC5 (M5 serotype) and the in‐frame isogenic mutant HSC5Δ htrA to determine whether HtrA contributes to the maturation of other GAS virulence determinants. Mutanolysin cell wall extracts and secreted proteins were arrayed by 2‐DE and identified by MALDI‐TOF PMF analysis. HSC5Δ htrA had elevated levels of cell wall‐associated M protein, whilst the supernatant had higher concentrations of M protein fragments and a reduced amount of mature SpeB protease, compared to wild‐type (WT). Western blot analysis and protease assays revealed a delay in the maturation of SpeB in the HSC5Δ htrA supernatant. HtrA was unable to directly process SpeB zymogen (proSpeB) to the active form in vitro . We therefore conclude that HtrA plays an indirect role in the maturation of cysteine protease SpeB.