Cellular localization of bacterial Sec translocase

Haaksma, A.G. (2016) Cellular localization of bacterial Sec translocase. Bachelor's Thesis, Biology.

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Abstract

The Sec pathway in bacteria facilitates secretory and membrane protein translocation across or into the cytoplasmic membrane. In the post-translational pathway, the protein chaperone SecB addresses secretory proteins to the pore forming SecYEG complex. The ATPase SecA provides energy that is needed for protein excretion through this pore. In the co-translational pathway, membrane proteins are recognized by the Signal Recognition Particle (SRP) which also directs to the SecYEG complex. Opening of a lateral gate in the pore facilitates insertion of the membrane protein in the membrane. The membrane associated proteins YidC and SecDFyajC support protein translocation. Extensive research has been performed on cellular localization of the primary components of the Sec system, SecA and SecYEG. Localization of the Sec components are thought to be related with sites of cell wall synthesis, as well as distribution of anionic lipids over the membrane. In rod-shaped gram-positive bacteria, as well as in gram negative bacteria, these factors induce a helical distribution of the Sec proteins over the membrane. In coccus-shaped gram-positive bacteria, it is thought that the Sec machinery is located at the septum, or in a specific site near the septum: the ExPortal. However, research techniques varied in different studies. In many researches, Sec proteins were overexpressed. Also different microscope techniques were used to visualize the proteins. Recent research on localization of the Sec translocation machinery gave aberrant results, which could be due to use of new techniques (genomic integration and TIRF or PALM microscopy). A better representation of the living cell can be generated with these techniques, which makes them promising for further research on localization the Sec pathway.

Item Type:	Thesis (Bachelor's Thesis)
Degree programme:	Biology
Thesis type:	Bachelor's Thesis
Language:	English
Date Deposited:	15 Feb 2018 08:24
Last Modified:	15 Feb 2018 08:24
URI:	https://fse.studenttheses.ub.rug.nl/id/eprint/14427

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