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首页> 外文期刊>Infection and immunity >Role for Serine Protease HtrA (DegP) of Streptococcus pyogenes in the Biogenesis of Virulence Factors SpeB and the Hemolysin Streptolysin S
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Role for Serine Protease HtrA (DegP) of Streptococcus pyogenes in the Biogenesis of Virulence Factors SpeB and the Hemolysin Streptolysin S

机译：化脓性链球菌的丝氨酸蛋白酶HtrA（DegP）在毒力因子SpeB和溶血素链球菌溶血素S的生物合成中的作用

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The serine protease HtrA is involved in the folding and maturation of secreted proteins, as well as in the degradation of proteins that misfold during secretion. Depletion of HtrA has been shown to affect the sensitivity of many organisms to thermal and environmental stresses, as well as being essential for virulence in many pathogens. In the present study, we compared the behaviors of several different HtrA mutants of the gram-positive pathogen Streptococcus pyogenes (group A streptococcus). Consistent with prior reports, insertional inactivation of htrA, the gene that encodes HtrA, resulted in a mutant that grew poorly at 37°C. However, an identical phenotype was observed when a similar polar insertion was placed immediately downstream of htrA in the streptococcal chromosome, suggesting that the growth defect of the insertion mutant was not a direct result of insertional inactivation of htrA. This conclusion was supported by the observation that a nonpolar deletion mutation of htrA did not produce the growth defect. However, this mutation did affect the production of several secreted virulence factors whose biogenesis requires extensive processing. For the SpeB cysteine protease, the loss of HtrA was associated with a failure to proteolytically process the zymogen to an active protease. For the streptolysin S hemolysin, a dramatic increase in hemolytic activity resulted from the depletion of HtrA. Interestingly, HtrA-deficient mutants were not attenuated in a murine model of subcutaneous infection. These data add to the growing body of information that implies an important role for HtrA in the biogenesis of secreted proteins in gram-positive bacteria.
机译：丝氨酸蛋白酶HtrA参与分泌蛋白的折叠和成熟，以及分泌过程中错误折叠的蛋白的降解。业已证明，HtrA的消耗会影响许多生物体对热和环境压力的敏感性，并且对许多病原体的毒力至关重要。在本研究中，我们比较了革兰氏阳性病原体化脓性链球菌（A组链球菌）的几种不同的HtrA突变体的行为。与以前的报道一致，编码HtrA的基因 htrA 的插入失活导致突变体在37°C下生长较差。但是，当在链球菌染色体中的 htrA 的下游放置相似的极性插入片段时，观察到相同的表型，这表明插入突变体的生长缺陷不是插入失活的直接结果。 > htrA 。观察到的结论是 htrA 的非极性缺失突变不会产生生长缺陷。但是，此突变确实影响了几种分泌的毒力因子的产生，这些因子的生物发生需要大量加工。对于SpeB半胱氨酸蛋白酶，HtrA的丧失与将酶原蛋白水解加工成活性蛋白酶的失败有关。对于链球菌溶血素S溶血素，溶血活性的显着增加是由于HtrA的消耗。有趣的是，在皮下感染的鼠模型中，HtrA缺陷型突变体没有被减弱。这些数据增加了信息的增长，这意味着HtrA在革兰氏阳性细菌分泌蛋白的生物合成中起着重要作用。

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