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Article: The two PPX-GppA homologues from Mycobacterium tuberculosis have distinct biochemical activities

TitleThe two PPX-GppA homologues from Mycobacterium tuberculosis have distinct biochemical activities
Authors
Issue Date2012
PublisherPublic Library of Science. The Journal's web site is located at http://www.plosone.org/home.action
Citation
Plos One, 2012, v. 7 n. 8 How to Cite?
AbstractInorganic polyphosphate (poly-P), guanosine pentaphosphate (pppGpp) and guanosine tetraphosphate (ppGpp) are ubiquitous in bacteria. These molecules play a variety of important physiological roles associated with stress resistance, persistence, and virulence. In the bacterial pathogen Mycobacterium tuberculosis, the identities of the proteins responsible for the metabolism of polyphosphate and (p)ppGpp remain to be fully established. M. tuberculosis encodes two PPX-GppA homologues, Rv0496 (MTB-PPX1) and Rv1026, which share significant sequence similarity with bacterial exopolyphosphatase (PPX) and guanosine pentaphosphate 5′-phosphohydrolase (GPP) proteins. Here we delineate the respective biochemical activities of the Rv0496 and Rv1026 proteins and benchmark these against the activities of the PPX and GPP proteins from Escherichia coli. We demonstrate that Rv0496 functions as an exopolyphosphatase, showing a distinct preference for relatively short-chain poly-P substrates. In contrast, Rv1026 has no detectable exopolyphosphatase activities. Analogous to the E. coli PPX and GPP enzymes, the exopolyphosphatase activities of Rv0496 are inhibited by pppGpp and, to a lesser extent, by ppGpp alarmones, which are produced during the bacterial stringent response. However, neither Rv0496 nor Rv1026 have the ability to hydrolyze pppGpp to ppGpp; a reaction catalyzed by E. coli PPX and GPP. Both the Rv0496 and Rv1026 proteins have modest ATPase and to a lesser extent ADPase activities. pppGpp alarmones inhibit the ATPase activities of Rv1026 and, to a lesser extent, the ATPase activities of Rv0496. We conclude that PPX-GppA family proteins may not possess all the catalytic activities implied by their name and may play distinct biochemical roles involved in polyphosphate and (p)ppGpp metabolic pathways. © 2012 2012 Choi et al.
Persistent Identifierhttp://hdl.handle.net/10722/161504
ISSN
2015 Impact Factor: 3.057
2015 SCImago Journal Rankings: 1.395
PubMed Central ID
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorChoi, MYen_HK
dc.contributor.authorWang, Yen_HK
dc.contributor.authorWong, LLYen_HK
dc.contributor.authorLu, Bten_HK
dc.contributor.authorChen, Wyen_HK
dc.contributor.authorHuang, JDen_HK
dc.contributor.authorTanner, JAen_HK
dc.contributor.authorWatt, RMen_HK
dc.date.accessioned2012-08-29T07:13:48Z-
dc.date.available2012-08-29T07:13:48Z-
dc.date.issued2012en_HK
dc.identifier.citationPlos One, 2012, v. 7 n. 8en_HK
dc.identifier.issn1932-6203en_HK
dc.identifier.urihttp://hdl.handle.net/10722/161504-
dc.description.abstractInorganic polyphosphate (poly-P), guanosine pentaphosphate (pppGpp) and guanosine tetraphosphate (ppGpp) are ubiquitous in bacteria. These molecules play a variety of important physiological roles associated with stress resistance, persistence, and virulence. In the bacterial pathogen Mycobacterium tuberculosis, the identities of the proteins responsible for the metabolism of polyphosphate and (p)ppGpp remain to be fully established. M. tuberculosis encodes two PPX-GppA homologues, Rv0496 (MTB-PPX1) and Rv1026, which share significant sequence similarity with bacterial exopolyphosphatase (PPX) and guanosine pentaphosphate 5′-phosphohydrolase (GPP) proteins. Here we delineate the respective biochemical activities of the Rv0496 and Rv1026 proteins and benchmark these against the activities of the PPX and GPP proteins from Escherichia coli. We demonstrate that Rv0496 functions as an exopolyphosphatase, showing a distinct preference for relatively short-chain poly-P substrates. In contrast, Rv1026 has no detectable exopolyphosphatase activities. Analogous to the E. coli PPX and GPP enzymes, the exopolyphosphatase activities of Rv0496 are inhibited by pppGpp and, to a lesser extent, by ppGpp alarmones, which are produced during the bacterial stringent response. However, neither Rv0496 nor Rv1026 have the ability to hydrolyze pppGpp to ppGpp; a reaction catalyzed by E. coli PPX and GPP. Both the Rv0496 and Rv1026 proteins have modest ATPase and to a lesser extent ADPase activities. pppGpp alarmones inhibit the ATPase activities of Rv1026 and, to a lesser extent, the ATPase activities of Rv0496. We conclude that PPX-GppA family proteins may not possess all the catalytic activities implied by their name and may play distinct biochemical roles involved in polyphosphate and (p)ppGpp metabolic pathways. © 2012 2012 Choi et al.en_HK
dc.languageeng-
dc.publisherPublic Library of Science. The Journal's web site is located at http://www.plosone.org/home.actionen_HK
dc.relation.ispartofPLoS ONEen_HK
dc.rightsCreative Commons: Attribution 3.0 Hong Kong License-
dc.titleThe two PPX-GppA homologues from Mycobacterium tuberculosis have distinct biochemical activitiesen_HK
dc.typeArticleen_HK
dc.identifier.emailChen, Wy: chenwy@hku.hken_HK
dc.identifier.emailTanner, JA: jatanner@hku.hken_HK
dc.identifier.emailWatt, RM: rmwatt@hku.hken_HK
dc.identifier.authorityChen, Wy=rp01487en_HK
dc.identifier.authorityTanner, JA=rp00495en_HK
dc.identifier.authorityWatt, RM=rp00043en_HK
dc.description.naturepublished_or_final_version-
dc.identifier.doi10.1371/journal.pone.0042561en_HK
dc.identifier.pmid22880033-
dc.identifier.pmcidPMC3411833-
dc.identifier.scopuseid_2-s2.0-84864555459en_HK
dc.identifier.hkuros205925-
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-84864555459&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume7en_HK
dc.identifier.issue8en_HK
dc.identifier.eissn1932-6203-
dc.identifier.isiWOS:000307284100129-
dc.publisher.placeUnited Statesen_HK
dc.identifier.scopusauthoridChoi, MY=8309672900en_HK
dc.identifier.scopusauthoridWang, Y=48662984600en_HK
dc.identifier.scopusauthoridWong, LLY=36128985900en_HK
dc.identifier.scopusauthoridLu, Bt=55327056900en_HK
dc.identifier.scopusauthoridChen, Wy=37100973400en_HK
dc.identifier.scopusauthoridHuang, JD=54784706100en_HK
dc.identifier.scopusauthoridTanner, JA=35513993000en_HK
dc.identifier.scopusauthoridWatt, RM=7102907536en_HK

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