The effect of protein acetylation on the formation and processing of inclusion bodies and endogenous protein aggregates in Escherichia coli cells.
BACKGROUND
Acetylation of lysine residues is a reversible post-translational modification conserved from bacteria to humans. Several recent studies have revealed hundreds of lysine-acetylated proteins in various bacteria; however, the physiological role of these modifications remains largely unknown. Since lysine acetylation changes the size and charge of proteins and thereby may affect their conformation, we assumed that lysine acetylation can stimulate aggregation of proteins, especially for overproduced recombinant proteins that form inclusion bodies.


RESULTS
To verify this assumption, we used Escherichia coli strains that overproduce aggregation-prone VP1GFP protein. We found that in ΔackA-pta cells, which display diminished protein acetylation, inclusion bodies were formed with a delay and processed faster than in the wild-type cells. Moreover, in ΔackA-pta cells, inclusion bodies exhibited significantly increased specific GFP fluorescence. In CobB deacetylase-deficient cells, in which protein acetylation was enhanced, the formation of inclusion bodies was increased and their processing was significantly inhibited. Similar results were obtained with regard to endogenous protein aggregates formed during the late stationary phase in ΔackA-pta and ΔcobB cells.


CONCLUSIONS
Our studies revealed that protein acetylation affected the aggregation of endogenous E. coli proteins and the yield, solubility, and biological activity of a model recombinant protein. In general, decreased lysine acetylation inhibited the formation of protein aggregates, whereas increased lysine acetylation stabilized protein aggregates. These findings should be considered during the designing of efficient strategies for the production of recombinant proteins in E. coli cells.
Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308, Gdansk, Poland.
Dorota
D
Kuczyńska-Wiśnik
Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308, Gdansk, Poland.
María
M
Moruno-Algara
Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308, Gdansk, Poland.
Karolina
K
Stojowska-Swędrzyńska
Department of General and Medical Biochemistry, Faculty of Biology, University of Gdansk, Wita Stwosza 59, 80-308, Gdansk, Poland. ewa.laskowska@biol.ug.edu.pl.
Ewa
http://orcid.org/0000-0002-7138-1125
E
Laskowska
D000107:Acetylation; D004926:Escherichia coli / Q000378:metabolism*; D006801:Humans; D002479:Inclusion Bodies / Q000378:metabolism*; D008239:Lysine / Q000378:metabolism*; D066329:Protein Aggregates; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism
D066329:Protein Aggregates; D011994:Recombinant Proteins; D008239:Lysine
Inclusion bodies; Lysine acetylation; Protein aggregates; Recombinant proteins