Escherichia coli HdeB Is an Acid Stress Chaperone

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dc.contributor.author Kern, Renee
dc.contributor.author Malki, Abderrahim
dc.contributor.author Abdallah, Jad
dc.contributor.author Tagourti, Jihen
dc.contributor.author Richarme, Gilbert
dc.date.accessioned 2016-07-19T06:36:25Z
dc.date.available 2016-07-19T06:36:25Z
dc.date.copyright 2006 en_US
dc.date.issued 2016-07-19
dc.identifier.issn 0021-9193 en_US
dc.identifier.uri http://hdl.handle.net/10725/4160
dc.description.abstract We cloned, expressed, and purified the hdeB gene product, which belongs to the hdeAB acid stress operon. We extracted HdeB from bacteria by the osmotic-shock procedure and purified it to homogeneity by ionexchange chromatography and hydroxyapatite chromatography. Its identity was confirmed by mass spectrometry analysis. HdeB has a molecular mass of 10 kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, which matches its expected molecular mass. We purified the acid stress chaperone HdeA in parallel in order to compare the two chaperones. The hdeA and hdeB mutants both display reduced viability upon acid stress, and only the HdeA/HdeB expression plasmid can restore their viability to close to the wild-type level, suggesting that both proteins are required for optimal protection of the bacterial periplasm against acid stress. Periplasmic extracts from both mutants aggregate at acidic pH, suggesting that HdeA and HdeB are required for protein solubilization. At pH 2, the aggregation of periplasmic extracts is prevented by the addition of HdeA, as previously reported, but is only slightly reduced by HdeB. At pH 3, however, HdeB is more efficient than HdeA in preventing periplasmic-protein aggregation. The solubilization of several model substrate proteins at acidic pH supports the hypothesis that, in vitro, HdeA plays a major role in protein solubilization at pH 2 and that both proteins are involved in protein solubilization at pH 3. Like HdeA, HdeB exposes hydrophobic surfaces at acidic pH, in accordance with the appearance of its chaperone properties at acidic pH. HdeB, like HdeA, dissociates from dimers at neutral pH into monomers at acidic pHs, but its dissociation is complete at pH 3 whereas that of HdeA is complete at a more acidic pH. Thus, we can conclude that Escherichia coli possesses two acid stress chaperones that prevent periplasmic-protein aggregation at acidic pH. en_US
dc.language.iso en en_US
dc.title Escherichia coli HdeB Is an Acid Stress Chaperone en_US
dc.type Article en_US
dc.description.version Published en_US
dc.author.school SOP en_US
dc.author.idnumber 200703820 en_US
dc.author.department Pharmaceutical Sciences Department en_US
dc.description.embargo N/A en_US
dc.relation.journal Journal of Bacteriology en_US
dc.article.pages 603-610 en_US
dc.identifier.doi http://dx.doi.org/10.1128/JB.01522-06 en_US
dc.identifier.ctation Kern, R., Malki, A., Abdallah, J., Tagourti, J., & Richarme, G. (2007). Escherichia coli HdeB is an acid stress chaperone. Journal of bacteriology, 189(2), 603-610. en_US
dc.author.email jabdallah@lau.edu.lb en_US
dc.identifier.tou http://libraries.lau.edu.lb/research/laur/terms-of-use/articles.php en_US
dc.identifier.url http://jb.asm.org/content/189/2/603.full.pdf+html en_US
dc.orcid.id https://orcid.org/0000-0001-5267-4953 en_US

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