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Article: The duality of LysU, a catalyst for both Ap4A and Ap3A formation

TitleThe duality of LysU, a catalyst for both Ap4A and Ap3A formation
Authors
Issue Date2006
PublisherWiley-Blackwell Publishing Ltd.. The Journal's web site is located at http://www.febsjournal.org/
Citation
FEBS Journal, 2006, v. 273 n. 15, p. 3534-3544 How to Cite?
AbstractHeat shock inducible lysyl-tRNA synthetase of Escherichia coli (LysU) is known to be a highly efficient diadenosine 5′,5‴-P 1,P4-tetraphosphate (Ap4A) synthase. However, we use an ion-exchange HPLC technique to demonstrate that active LysU mixtures actually have a dual catalytic activity, initially producing Ap4A from ATP, before converting that tetraphosphate to a triphosphate. LysU appears to be an effective diadenosine 5′,5‴-P1,P 3-triphosphate (Ap3A) synthase. Mechanistic investigations reveal that Ap3A formation requires: (a) that the second step of Ap4A formation is slightly reversible, thereby leading to a modest reappearance of adenylate intermediate; and (b) that phosphate is present to trap the intermediate (either as inorganic phosphate, as added ADP, or as ADP generated in situ from inorganic phosphate). Ap3A forms readily from Ap4A in the presence of such phosphate-based adenylate traps (via a 'reverse-trap' mechanism). LysU is also clearly demonstrated to exist in a phosphorylated state that is more physically robust as a catalyst of Ap 4A formation than the nonphosphorylated state. However, phosphorylated LysU shows only marginally improved catalytic efficiency. We note that Ap3A effects have barely been studied in prokaryotic organisms. By contrast, there is a body of literature that describes Ap3A and Ap4A having substantially different functions in eukaryotic cells. Our data suggest that Ap3A and Ap4A biosynthesis could be linked together through a single prokaryotic dual 'synthase' enzyme. Therefore, in our view there is a need for new research into the effects and impact of Ap3A alone and the intracellular [Ap3A]/[Ap4A] ratio on prokaryotic organisms. © 2006 The Authors.
Persistent Identifierhttp://hdl.handle.net/10722/147540
ISSN
2015 Impact Factor: 4.237
2015 SCImago Journal Rankings: 2.141
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorWright, Men_US
dc.contributor.authorBoonyalai, Nen_US
dc.contributor.authorTanner, JAen_US
dc.contributor.authorHindley, ADen_US
dc.contributor.authorMiller, ADen_US
dc.date.accessioned2012-05-29T06:04:27Z-
dc.date.available2012-05-29T06:04:27Z-
dc.date.issued2006en_US
dc.identifier.citationFEBS Journal, 2006, v. 273 n. 15, p. 3534-3544en_US
dc.identifier.issn1742-464Xen_US
dc.identifier.urihttp://hdl.handle.net/10722/147540-
dc.description.abstractHeat shock inducible lysyl-tRNA synthetase of Escherichia coli (LysU) is known to be a highly efficient diadenosine 5′,5‴-P 1,P4-tetraphosphate (Ap4A) synthase. However, we use an ion-exchange HPLC technique to demonstrate that active LysU mixtures actually have a dual catalytic activity, initially producing Ap4A from ATP, before converting that tetraphosphate to a triphosphate. LysU appears to be an effective diadenosine 5′,5‴-P1,P 3-triphosphate (Ap3A) synthase. Mechanistic investigations reveal that Ap3A formation requires: (a) that the second step of Ap4A formation is slightly reversible, thereby leading to a modest reappearance of adenylate intermediate; and (b) that phosphate is present to trap the intermediate (either as inorganic phosphate, as added ADP, or as ADP generated in situ from inorganic phosphate). Ap3A forms readily from Ap4A in the presence of such phosphate-based adenylate traps (via a 'reverse-trap' mechanism). LysU is also clearly demonstrated to exist in a phosphorylated state that is more physically robust as a catalyst of Ap 4A formation than the nonphosphorylated state. However, phosphorylated LysU shows only marginally improved catalytic efficiency. We note that Ap3A effects have barely been studied in prokaryotic organisms. By contrast, there is a body of literature that describes Ap3A and Ap4A having substantially different functions in eukaryotic cells. Our data suggest that Ap3A and Ap4A biosynthesis could be linked together through a single prokaryotic dual 'synthase' enzyme. Therefore, in our view there is a need for new research into the effects and impact of Ap3A alone and the intracellular [Ap3A]/[Ap4A] ratio on prokaryotic organisms. © 2006 The Authors.en_US
dc.languageengen_US
dc.publisherWiley-Blackwell Publishing Ltd.. The Journal's web site is located at http://www.febsjournal.org/en_US
dc.relation.ispartofFEBS Journalen_US
dc.subject.meshBlotting, Westernen_US
dc.subject.meshCatalysisen_US
dc.subject.meshChromatography, High Pressure Liquiden_US
dc.subject.meshChromatography, Ion Exchangeen_US
dc.subject.meshDinucleoside Phosphates - Biosynthesisen_US
dc.subject.meshElectrophoresis, Polyacrylamide Gelen_US
dc.subject.meshEscherichia Coli - Enzymologyen_US
dc.subject.meshLysine-Trna Ligase - Metabolismen_US
dc.subject.meshNuclear Magnetic Resonance, Biomolecularen_US
dc.subject.meshPhosphorylationen_US
dc.titleThe duality of LysU, a catalyst for both Ap4A and Ap3A formationen_US
dc.typeArticleen_US
dc.identifier.emailTanner, JA:jatanner@hku.hken_US
dc.identifier.authorityTanner, JA=rp00495en_US
dc.description.naturelink_to_OA_fulltexten_US
dc.identifier.doi10.1111/j.1742-4658.2006.05361.xen_US
dc.identifier.pmid16884494en_US
dc.identifier.scopuseid_2-s2.0-33746162021en_US
dc.identifier.hkuros120526-
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-33746162021&selection=ref&src=s&origin=recordpageen_US
dc.identifier.volume273en_US
dc.identifier.issue15en_US
dc.identifier.spage3534en_US
dc.identifier.epage3544en_US
dc.identifier.isiWOS:000239120300013-
dc.publisher.placeUnited Kingdomen_US
dc.identifier.scopusauthoridWright, M=11139776500en_US
dc.identifier.scopusauthoridBoonyalai, N=14043267300en_US
dc.identifier.scopusauthoridTanner, JA=35513993000en_US
dc.identifier.scopusauthoridHindley, AD=36860704800en_US
dc.identifier.scopusauthoridMiller, AD=7406230808en_US
dc.identifier.citeulike765487-

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