Date of Award
Doctor of Philosophy (PhD)
Microbiology and Immunology
An under-investigated target of lysine acetylation is the bacterial ribosome. Although lysine acetylations on the ribosome are common and conversed in diverse bacterial species, little work has been done to understand how lysine acetylation affects the bacterial ribosome. The goal of this work is to determine if lysine acetylation has functional impact on the bacterial ribosome.I have identified in vitro and in vivo effects of nonenzymatic, AcP-dependent lysine acetylation on translation and the ribosome. In vitro acetylation of transcription-translation reactions causes a translation-specific defect that is unaffected by the addition of the CobB deacetylase. This suggests certain AcP-sensitive residues that are part of the translation machinery can inhibit translation, and these acetylations are not reversible. In vivo, I have demonstrated that high acetylation bacterial cultures have a ribosome population that favors the presence of dissociated 30S and 50S subunits over intact 70S ribosomes in stationary phase. This is true for cultures that are acetylation high due to manipulation and cultures that are acetylation high due to media manipulation. This suggests that the impact of nonenzymatic lysine acetylation on the ribosome is linked to central carbon metabolism, due to the relationship between AcP levels and carbon flux. I have also demonstrated that there is some contribution by the CobB deacetylase to the subunit skew pattern. However, complications caused by the sensitivity of the pattern to growth conditions have stymied efforts to determine if the shift is caused primarily by CobB-sensitive acetylated lysines or a mixture of CobB-sensitive and -insensitive acetylated lysines. Finally, preliminary mass spectrometry data of 30S, 50S, and 70S fractions from wild-type E. coli grown in a rich medium until stationary phase have allowed me to identify 18 acetylated lysine that are only observed in the subunit fractions. Of these acetylations, acetylated lysines on uS7 and bL12 have functional roles that make them promising targets for future studies into the mechanistic effects of lysine acetylation on the ribosome.
Feid, Sarah Caldwell, "Investigating the Impact of Nonenzymatic Lysine Acetylation on the Function of the Bacterial Ribosome" (2023). Dissertations. 4017.
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Copyright © 2023 Sarah Caldwell Feid