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Electronic and geometric structures of the organophosphate-degrading enzyme from Agrobacterium radiobacter (OpdA)

Ely, Fernanda; Hadler, Kieran S; Mitic, Natasa; Gahan, Lawrence; Ollis, David; Plugis, Nicholas M.; Russo, Marie T; Larrabee, James A; Schenk, Gerhard

Description

The organophosphate-degrading enzyme from Agrobacterium radiobacter (OpdA) is a highly efficient catalyst for the degradation of pesticides and some nerve agents such as sarin. OpdA requires two metal ions for catalytic activity, and hydrolysis is initiated by a nucleophilic hydroxide that is bound to one of these metal ions. The precise location of this nucleophile has been contentious, with both a terminal and a metal-ion-bridging hydroxide as likely candidates. Here, we employed magnetic...[Show more]

dc.contributor.authorEly, Fernanda
dc.contributor.authorHadler, Kieran S
dc.contributor.authorMitic, Natasa
dc.contributor.authorGahan, Lawrence
dc.contributor.authorOllis, David
dc.contributor.authorPlugis, Nicholas M.
dc.contributor.authorRusso, Marie T
dc.contributor.authorLarrabee, James A
dc.contributor.authorSchenk, Gerhard
dc.date.accessioned2015-12-10T22:50:59Z
dc.identifier.issn0949-8257
dc.identifier.urihttp://hdl.handle.net/1885/58844
dc.description.abstractThe organophosphate-degrading enzyme from Agrobacterium radiobacter (OpdA) is a highly efficient catalyst for the degradation of pesticides and some nerve agents such as sarin. OpdA requires two metal ions for catalytic activity, and hydrolysis is initiated by a nucleophilic hydroxide that is bound to one of these metal ions. The precise location of this nucleophile has been contentious, with both a terminal and a metal-ion-bridging hydroxide as likely candidates. Here, we employed magnetic circular dichroism to probe the electronic and geometric structures of the Co(II)-reconstituted dinuclear metal center in OpdA. In the resting state the metal ion in the more secluded a site is five-coordinate, whereas the Co(II) in the solvent-exposed β site is predominantly sixcoordinate with two terminal water ligands. Addition of the slow substrate diethyl 4-methoxyphenyl phosphate does not affect the a site greatly but lowers the coordination number of the β site to five. A reduction in the exchange coupling constant indicates that substrate binding also triggers a shift of the l-hydroxide into a pseudoterminal position in the coordination sphere of either the α or the β metal ion. Mechanistic implications of these observations are discussed.
dc.publisherSpringer
dc.sourceJournal of Biological Inorganic Chemistry
dc.subjectKeywords: bacterial enzyme; cobalt complex; diethyl 4 methoxyphenyl phosphate; hydroxide; organophosphate degrading enzyme; phosphate; unclassified drug; article; circular dichroism; complex formation; controlled study; crystal structure; enzyme structure; enzyme s Catalytic mechanism; Dinuclear metallohydrolase; Magnetic circular dichroism; X-ray crystal structures
dc.titleElectronic and geometric structures of the organophosphate-degrading enzyme from Agrobacterium radiobacter (OpdA)
dc.typeJournal article
local.description.notesImported from ARIES
local.identifier.citationvolume16
dc.date.issued2011
local.identifier.absfor030401 - Biologically Active Molecules
local.identifier.ariespublicationu4005981xPUB461
local.type.statusPublished Version
local.contributor.affiliationEly, Fernanda, University of Queensland
local.contributor.affiliationHadler, Kieran S, University of Queensland
local.contributor.affiliationMitic, Natasa, University of Queensland
local.contributor.affiliationGahan, Lawrence, University of Queensland
local.contributor.affiliationOllis, David, College of Physical and Mathematical Sciences, ANU
local.contributor.affiliationPlugis, Nicholas M., Middlebury College
local.contributor.affiliationRusso, Marie T, Middlebury College
local.contributor.affiliationLarrabee, James A, Middlebury College
local.contributor.affiliationSchenk, Gerhard, University of Queensland
local.description.embargo2037-12-31
local.bibliographicCitation.issue5
local.bibliographicCitation.startpage777
local.bibliographicCitation.lastpage787
local.identifier.doi10.1007/s00775-011-0779-6
local.identifier.absseo970103 - Expanding Knowledge in the Chemical Sciences
dc.date.updated2016-02-24T10:24:13Z
local.identifier.scopusID2-s2.0-80051552042
local.identifier.thomsonID000290773500010
CollectionsANU Research Publications

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