DNA supercoiling differences in bacteria result from disparate DNA gyrase activation by polyamines.
PLoS Genet
; 16(10): e1009085, 2020 10.
Article
in En
| MEDLINE
| ID: mdl-33125364
ABSTRACT
DNA supercoiling is essential for all living cells because it controls all processes involving DNA. In bacteria, global DNA supercoiling results from the opposing activities of topoisomerase I, which relaxes DNA, and DNA gyrase, which compacts DNA. These enzymes are widely conserved, sharing >91% amino acid identity between the closely related species Escherichia coli and Salmonella enterica serovar Typhimurium. Why, then, do E. coli and Salmonella exhibit different DNA supercoiling when experiencing the same conditions? We now report that this surprising difference reflects disparate activation of their DNA gyrases by the polyamine spermidine and its precursor putrescine. In vitro, Salmonella DNA gyrase activity was sensitive to changes in putrescine concentration within the physiological range, whereas activity of the E. coli enzyme was not. In vivo, putrescine activated the Salmonella DNA gyrase and spermidine the E. coli enzyme. High extracellular Mg2+ decreased DNA supercoiling exclusively in Salmonella by reducing the putrescine concentration. Our results establish the basis for the differences in global DNA supercoiling between E. coli and Salmonella, define a signal transduction pathway regulating DNA supercoiling, and identify potential targets for antibacterial agents.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Salmonella typhimurium
/
DNA, Superhelical
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DNA Topoisomerases, Type I
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DNA Gyrase
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Escherichia coli
Language:
En
Journal:
PLoS Genet
Journal subject:
GENETICA
Year:
2020
Document type:
Article
Affiliation country: