کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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5673493 | 1593632 | 2017 | 11 صفحه PDF | دانلود رایگان |
In Streptococcus pneumoniae TIGR4, genes encoding a SecY2A2 accessory Sec system are present within a locus encoding a serine-rich repeat surface protein PsrP. Mutant strains deleted in secA2 or psrP were deficient in biofilm formation, while the ÎsecA2 mutant was reduced in binding to airway epithelial cells. Cell wall protein (CWP) fractions from the ÎsecA2 mutant, but not from the ÎpsrP mutant, were reduced in haemolytic (pneumolysin) activity. Contact-dependent pneumolysin (Ply) activity of wild type TIGR4 cells was ten-fold greater than that of ÎsecA2 mutant cells suggesting that Ply was not active at the ÎsecA2 cell surface. Ply protein was found to be present in the CWP fraction from the ÎsecA2 mutant, but showed aberrant electrophoretic migration indicative of protein modification. Proteomic analyses led to the discovery that the ÎsecA2 mutant CWP fraction was deficient in two glycosidases as well as other enzymes involved in carbohydrate metabolism. Taken collectively the results suggest that positioning of Ply into the cell wall compartment in active form, together with glycosyl hydrolases and adhesins, requires a functional accessory Sec system.
Journal: Microbes and Infection - Volume 19, Issues 7â8, JulyâAugust 2017, Pages 402-412