PROBING THE FUNCTIONAL ROLE OF DIFFERENT REGIONS OF THE OsmY PROTEIN
Escherichia coli can adapt to various stress conditions in order to grow and <br /> <br /> survive, one of which is hyperosmotic stress. In overcoming hyperosmotic stress, <br /> <br /> E. coli and other bacteria usually activate several genes under the control of <br />...
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| Format: | Theses |
| Language: | Indonesia |
| Online Access: | https://digilib.itb.ac.id/gdl/view/30317 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | Escherichia coli can adapt to various stress conditions in order to grow and <br />
<br />
survive, one of which is hyperosmotic stress. In overcoming hyperosmotic stress, <br />
<br />
E. coli and other bacteria usually activate several genes under the control of <br />
<br />
common regulator proteins. The accumulation of regulatory proteins and gene <br />
<br />
transcriptions allows E. coli to provide resistance against stress. The osmotically <br />
<br />
inducible protein Y (OsmY) is a 20 kDa periplasmic protein (with a yet unknown <br />
<br />
function) is one such protein whose expression level increases up to 10-fold under <br />
<br />
hyperosmotic stress. OsmY is highly expressed in the stationary phase natively <br />
<br />
and under hyperosmotic shock conditions. It is believed that OsmY keeps the <br />
<br />
cytoplasmic membrane from shrinking by contacting the phospholipid interfaces <br />
<br />
surrounding the periplasmic space and likely assists in survival under <br />
<br />
hyperosmotic stress. Although the structure of OsmY is unknown, predictive <br />
<br />
modelling studies suggest a presence of a disordered N-terminal region and two <br />
<br />
membrane-binding bacterial OsmY and Nodulation (BON) domains separated by <br />
<br />
a 10 amino acid linker. The presence of BON domains in OsmY suggests that <br />
<br />
these domains may link the inner and outer membrane. Existing studies in the lab <br />
<br />
show that overexpression of OsmY helps growth in hyperosmotic environments. <br />
<br />
In this research, different structural regions in OsmY were probed to ascertain if <br />
<br />
they contribute to the function of OsmY. We systematically generated three <br />
<br />
truncation variants of OsmY wherein the N-terminus, a BON domain, and the <br />
<br />
linker were truncated respectively. Two additional variants were created wherein <br />
<br />
the linker between the BON domains were duplicated and triplicated. We observe <br />
<br />
that the removal of one of the BON domains severely impairs the ability of E. coli <br />
<br />
to survive at hyperosmotic stress. <br />
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