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Mycobacterium tuberculosis Protein PPE51 Interactions with Glucose and Glycerol Megan Murto, 2nd year |
Abstract
Escherichia coli is commonly used in place of Mycobacterium tuberculosis (Mtb) due to its lower pathogenicity and faster doubling rate, allowing for more convenient BSL-2 laboratory access and a shorter growth window. Previously, it was found that Mtb uses the PPE51 protein to take up disaccharides into the cell. Upon further experimentation, it was found that when glucose was supplemented into minimal media, the growth kinetics were not changed.
On the other hand, glycerol was found to increase the growth of the PPE51 CRISPER-strong mutants. From this, it was hypothesized that different carbon sources, specifically glucose and glycerol, would stabilize the PPE51 protein. Wild type (WT) E. coli expressed the Mtb protein PPE51 from the T7-inducible pET plasmid and a thermostability assay was used to examine the protein degradation at different temperature levels in 5°C increments, ranging from 35°C to 60°C. This experiment concluded that glycerol is used in order to stabilize the PPE51 protein at higher temperatures. Glucose is theorized to not stabilize the protein at higher temperatures, however the experiment should be repeated due to difficulties with the SDS-PAGE gel.
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