Protein trafficking in the cell envelope of Escherichia coli: Identification and characterisation of a novel chaperone
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
The cell envelope of Gram-negative bacteria, like Escherichia coli, is composed of a cytoplasmic membrane, a periplasmic space containing a peptidoglycan layer and an outer membrane. About 30 % of all proteins are localised in the cell envelope. These proteins have to be inserted into or translocated across the inner membrane by the SecYEG translocon. They are then chaperoned to their final destination by a network of chaperones. The broad aim of this work was to provide a better understanding of protein trafficking through the bacterial cell envelope. We have identified a novel membrane protein complex consisting of the periplasmic chaperone PpiD and the uncharacterised protein YfgM. Both are anchored in the inner membrane and have periplasmic domains. By co-immunoprecipitations and two-dimensional gel electrophoresis it could be demonstrated that YfgM and PpiD form a supercomplex with the SecYEG translocon. Furthermore, a chemical-genetic approach showed that YfgM is part of the periplasmic chaperone network that is essential for envelope protein biogenesis. Moreover, it could be shown that YfgM is required for the stability of the periplasmic chaperone HdeB. Finally, evidence that YfgM might also be involved in the lateral insertion of transmembrane domains was provided. In summary, this thesis details the identification and characterisation of a novel ancillary subunit of the SecYEG translocon that is involved in the periplasmic chaperone network in the cell envelope of Escherichia coli.
Place, publisher, year, edition, pages
Stockholm: Department of Biochemistry and Biophysics, Stockholm University , 2014. , 73 p.
Biochemistry and Molecular Biology
Research subject Biochemistry
IdentifiersURN: urn:nbn:se:su:diva-106277ISBN: 978-91-7447-944-7OAI: oai:DiVA.org:su-106277DiVA: diva2:735676
2014-09-25, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 16 B, Stockholm, 10:00 (English)
Koch, Hans-Georg, Professor
Daley, Daniel, Associate professor
At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.2014-09-032014-07-302014-08-19Bibliographically approved
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