Evolution of the bacterial nucleosidase PpnN and its relation to the stringent response

In our recent publication (Zhang et al., 2019), we demonstrate an interesting mode of regulation of purine metabolism unique to Proteobacteria. In this microreview, we would like to reflect on the ideas put forward, with special focus on protein domain architecture of the enzyme involved, its orthol...

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Main Authors: René Lysdal Bærentsen, Ditlev Egeskov Brodersen, Yong Everett Zhang
Format: Article
Language:English
Published: Shared Science Publishers OG 2019-07-01
Series:Microbial Cell
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Online Access:http://microbialcell.com/researcharticles/2019a-baerentsen-microbial-cell/
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author René Lysdal Bærentsen
Ditlev Egeskov Brodersen
Yong Everett Zhang
author_facet René Lysdal Bærentsen
Ditlev Egeskov Brodersen
Yong Everett Zhang
author_sort René Lysdal Bærentsen
collection DOAJ
description In our recent publication (Zhang et al., 2019), we demonstrate an interesting mode of regulation of purine metabolism unique to Proteobacteria. In this microreview, we would like to reflect on the ideas put forward, with special focus on protein domain architecture of the enzyme involved, its orthologues in plants, and the implications of the differential effects observed between binding of the two alarmone molecules, ppGpp (guanosine 3′,5′-bisdiphosphate) and pppGpp (guanosine-5′-triphosphate-3′-diphosphate). In our previous work, we showed that the Escherichia coli nucleotide 5′-monophosphate nucleosidase, PpnN, which is conserved in Proteobacteria, cleaves its preferred substrate, guanosine monophosphate (GMP), at a much higher rate in the presence of both pppGpp and ppGpp (Figure 1A). Structural analysis reveals that binding of pppGpp leads to a conformational change in the protein that exposes its active site, suggesting this is the reason for the observed increase in activity. Finally, point mutation of the alarmone-interacting residues show a defect in binding, resulting in (i) increased basal catalytic activity of PpnN and higher competitive fitness of E. coli in an environment with fluctuating nutrient levels, and (ii) increased bacterial sensitivity towards antibiotics. In contrast, complete loss of the ppnN gene has the inverse effect, i.e. reduced competitive growth and improved antibiotic tolerance. We used these observations to propose a model in which E. coli uses PpnN to balance the need of fitness (fast growth) against tolerance towards antibiotics to improve survival.
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spelling doaj-art-387449bbbfb94baaa3496e18aad1ce102025-08-20T02:57:37ZengShared Science Publishers OGMicrobial Cell2311-26382019-07-016945045310.15698/mic2019.09.692Evolution of the bacterial nucleosidase PpnN and its relation to the stringent responseRené Lysdal Bærentsen0Ditlev Egeskov Brodersen1Yong Everett Zhang2Department of Molecular Biology and Genetics, Aarhus University, DK-8000 Aarhus C, Denmark.Department of Molecular Biology and Genetics, Aarhus University, DK-8000 Aarhus C, Denmark.Department of Biology, University of Copenhagen, DK- 2200 Copenhagen N, Denmark.In our recent publication (Zhang et al., 2019), we demonstrate an interesting mode of regulation of purine metabolism unique to Proteobacteria. In this microreview, we would like to reflect on the ideas put forward, with special focus on protein domain architecture of the enzyme involved, its orthologues in plants, and the implications of the differential effects observed between binding of the two alarmone molecules, ppGpp (guanosine 3′,5′-bisdiphosphate) and pppGpp (guanosine-5′-triphosphate-3′-diphosphate). In our previous work, we showed that the Escherichia coli nucleotide 5′-monophosphate nucleosidase, PpnN, which is conserved in Proteobacteria, cleaves its preferred substrate, guanosine monophosphate (GMP), at a much higher rate in the presence of both pppGpp and ppGpp (Figure 1A). Structural analysis reveals that binding of pppGpp leads to a conformational change in the protein that exposes its active site, suggesting this is the reason for the observed increase in activity. Finally, point mutation of the alarmone-interacting residues show a defect in binding, resulting in (i) increased basal catalytic activity of PpnN and higher competitive fitness of E. coli in an environment with fluctuating nutrient levels, and (ii) increased bacterial sensitivity towards antibiotics. In contrast, complete loss of the ppnN gene has the inverse effect, i.e. reduced competitive growth and improved antibiotic tolerance. We used these observations to propose a model in which E. coli uses PpnN to balance the need of fitness (fast growth) against tolerance towards antibiotics to improve survival.http://microbialcell.com/researcharticles/2019a-baerentsen-microbial-cell/ppGppYgdHLOGDUF4478DUF3412PAG
spellingShingle René Lysdal Bærentsen
Ditlev Egeskov Brodersen
Yong Everett Zhang
Evolution of the bacterial nucleosidase PpnN and its relation to the stringent response
Microbial Cell
ppGpp
YgdH
LOG
DUF4478
DUF3412
PAG
title Evolution of the bacterial nucleosidase PpnN and its relation to the stringent response
title_full Evolution of the bacterial nucleosidase PpnN and its relation to the stringent response
title_fullStr Evolution of the bacterial nucleosidase PpnN and its relation to the stringent response
title_full_unstemmed Evolution of the bacterial nucleosidase PpnN and its relation to the stringent response
title_short Evolution of the bacterial nucleosidase PpnN and its relation to the stringent response
title_sort evolution of the bacterial nucleosidase ppnn and its relation to the stringent response
topic ppGpp
YgdH
LOG
DUF4478
DUF3412
PAG
url http://microbialcell.com/researcharticles/2019a-baerentsen-microbial-cell/
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AT ditlevegeskovbrodersen evolutionofthebacterialnucleosidaseppnnanditsrelationtothestringentresponse
AT yongeverettzhang evolutionofthebacterialnucleosidaseppnnanditsrelationtothestringentresponse