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Title: WrpA Is an Atypical Flavodoxin Family Protein under Regulatory Control of the Brucella abortus General Stress Response System

Abstract

ABSTRACT The general stress response (GSR) system of the intracellular pathogenBrucella abortuscontrols the transcription of approximately 100 genes in response to a range of stress cues. The core genetic regulatory components of the GSR are required forB. abortussurvival under nonoptimal growth conditionsin vitroand for maintenance of chronic infection in anin vivomouse model. The functions of the majority of the genes in the GSR transcriptional regulon remain undefined.bab1_1070is among the most highly regulated genes in this regulon: its transcription is activated 20- to 30-fold by the GSR system under oxidative conditionsin vitro. We have solved crystal structures of Bab1_1070 and demonstrate that it forms a homotetrameric complex that resembles those of WrbA-type NADH:quinone oxidoreductases, which are members of the flavodoxin protein family. However,B. abortusWrbA-relatedprotein (WrpA) does not bind flavin cofactors with a high affinity and does not function as an NADH:quinone oxidoreductasein vitro. Soaking crystals with flavin mononucleotide (FMN) revealed a likely low-affinity binding site adjacent to the canonical WrbA flavin binding site. Deletion ofwrpA(ΔwrpA) does not compromise cell survival under acute oxidative stressin vitroor attenuate infection in cell-based or mouse models. However, a ΔwrpAstrain does elicit increased splenomegaly in a mouse model, suggesting that WrpA modulatesB. abortusinteraction with its mammalianmore » host. Despite high structural homology with canonical WrbA proteins, we propose thatB. abortusWrpA represents a functionally distinct member of the diverse flavodoxin family. IMPORTANCEBrucella abortusis an etiological agent of brucellosis, which is among the most common zoonotic diseases worldwide. The general stress response (GSR) regulatory system ofB. abortuscontrols the transcription of approximately 100 genes and is required for maintenance of chronic infection in a murine model; the majority of GSR-regulated genes remain uncharacterized. We presentin vitroandin vivofunctional and structural analyses of WrpA, whose expression is strongly induced by GSR under oxidative conditions. Though WrpA is structurally related to NADH:quinone oxidoreductases, it does not bind redox cofactors in solution, nor does it exhibit oxidoreductase activityin vitro. However, WrpA does affect spleen inflammation in a murine infection model. Our data provide evidence that WrpA forms a new functional class of WrbA/flavodoxin family proteins.« less

Authors:
; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
National Institutes of Health (NIH)
OSTI Identifier:
1415982
DOE Contract Number:
AC02-06CH11357
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Bacteriology; Journal Volume: 198; Journal Issue: 8
Country of Publication:
United States
Language:
English

Citation Formats

Herrou, Julien, Czyż, Daniel M., Willett, Jonathan W., Kim, Hye-Sook, Chhor, Gekleng, Babnigg, Gyorgy, Kim, Youngchang, Crosson, Sean, and Stock, A. M. WrpA Is an Atypical Flavodoxin Family Protein under Regulatory Control of the Brucella abortus General Stress Response System. United States: N. p., 2016. Web. doi:10.1128/JB.00982-15.
Herrou, Julien, Czyż, Daniel M., Willett, Jonathan W., Kim, Hye-Sook, Chhor, Gekleng, Babnigg, Gyorgy, Kim, Youngchang, Crosson, Sean, & Stock, A. M. WrpA Is an Atypical Flavodoxin Family Protein under Regulatory Control of the Brucella abortus General Stress Response System. United States. doi:10.1128/JB.00982-15.
Herrou, Julien, Czyż, Daniel M., Willett, Jonathan W., Kim, Hye-Sook, Chhor, Gekleng, Babnigg, Gyorgy, Kim, Youngchang, Crosson, Sean, and Stock, A. M. Mon . "WrpA Is an Atypical Flavodoxin Family Protein under Regulatory Control of the Brucella abortus General Stress Response System". United States. doi:10.1128/JB.00982-15.
@article{osti_1415982,
title = {WrpA Is an Atypical Flavodoxin Family Protein under Regulatory Control of the Brucella abortus General Stress Response System},
author = {Herrou, Julien and Czyż, Daniel M. and Willett, Jonathan W. and Kim, Hye-Sook and Chhor, Gekleng and Babnigg, Gyorgy and Kim, Youngchang and Crosson, Sean and Stock, A. M.},
abstractNote = {ABSTRACT The general stress response (GSR) system of the intracellular pathogenBrucella abortuscontrols the transcription of approximately 100 genes in response to a range of stress cues. The core genetic regulatory components of the GSR are required forB. abortussurvival under nonoptimal growth conditionsin vitroand for maintenance of chronic infection in anin vivomouse model. The functions of the majority of the genes in the GSR transcriptional regulon remain undefined.bab1_1070is among the most highly regulated genes in this regulon: its transcription is activated 20- to 30-fold by the GSR system under oxidative conditionsin vitro. We have solved crystal structures of Bab1_1070 and demonstrate that it forms a homotetrameric complex that resembles those of WrbA-type NADH:quinone oxidoreductases, which are members of the flavodoxin protein family. However,B. abortusWrbA-relatedprotein (WrpA) does not bind flavin cofactors with a high affinity and does not function as an NADH:quinone oxidoreductasein vitro. Soaking crystals with flavin mononucleotide (FMN) revealed a likely low-affinity binding site adjacent to the canonical WrbA flavin binding site. Deletion ofwrpA(ΔwrpA) does not compromise cell survival under acute oxidative stressin vitroor attenuate infection in cell-based or mouse models. However, a ΔwrpAstrain does elicit increased splenomegaly in a mouse model, suggesting that WrpA modulatesB. abortusinteraction with its mammalian host. Despite high structural homology with canonical WrbA proteins, we propose thatB. abortusWrpA represents a functionally distinct member of the diverse flavodoxin family. IMPORTANCEBrucella abortusis an etiological agent of brucellosis, which is among the most common zoonotic diseases worldwide. The general stress response (GSR) regulatory system ofB. abortuscontrols the transcription of approximately 100 genes and is required for maintenance of chronic infection in a murine model; the majority of GSR-regulated genes remain uncharacterized. We presentin vitroandin vivofunctional and structural analyses of WrpA, whose expression is strongly induced by GSR under oxidative conditions. Though WrpA is structurally related to NADH:quinone oxidoreductases, it does not bind redox cofactors in solution, nor does it exhibit oxidoreductase activityin vitro. However, WrpA does affect spleen inflammation in a murine infection model. Our data provide evidence that WrpA forms a new functional class of WrbA/flavodoxin family proteins.},
doi = {10.1128/JB.00982-15},
journal = {Journal of Bacteriology},
number = 8,
volume = 198,
place = {United States},
year = {Mon Feb 08 00:00:00 EST 2016},
month = {Mon Feb 08 00:00:00 EST 2016}
}