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Article: Crystal Structures of the Substrate Free-enzyme, and Reaction Intermediate of the HAD Superfamily Member, Haloacid Dehalogenase DehIVa from Burkholderia cepacia MBA4

TitleCrystal Structures of the Substrate Free-enzyme, and Reaction Intermediate of the HAD Superfamily Member, Haloacid Dehalogenase DehIVa from Burkholderia cepacia MBA4
Authors
KeywordsαHA dehalogenase
dehalogenase
HAD superfamily
low barrier hydrogen bond
normal mode analysis
Issue Date2007
PublisherAcademic Press. The Journal's web site is located at http://www.elsevier.com/locate/jmb
Citation
Journal Of Molecular Biology, 2007, v. 368 n. 3, p. 706-717 How to Cite?
AbstractDehIVa is a haloacid dehalogenase (EC 3.8.1.2) from the soil and water borne bacterium Burkholderia cepacia MBA4, which belongs to the functionally variable haloacid dehalogenase (HAD) superfamily of enzymes. The haloacid dehalogenases catalyse the removal of halides from haloacids resulting in a hydroxlated product. These enzymes are of interest for their potential to degrade recalcitrant halogenated environmental pollutants and their use in the synthesis of industrial chemicals. The haloacid dehalogenases utilise a nucleophilic attack on the substrate by an aspartic acid residue to form an enzyme-substrate ester bond and concomitantly cleaving of the carbon-halide bond and release of a hydroxylated product following ester hydrolysis. We present the crystal structures of both the substrate-free DehIVa refined to 1.93 Å resolution and DehIVa covalently bound to l-2-monochloropropanoate trapped as a reaction intermediate, refined to 2.7 Å resolution. Electron density consistent with a previously unidentified yet anticipated water molecule in the active site poised to donate its hydroxyl group to the product and its proton to the catalytic Asp11 is evident. It has been unclear how substrate enters the active site of this and related enzymes. The results of normal mode analysis (NMA) are presented and suggest a means whereby the predicted global dynamics of the enzyme allow for entry of the substrate into the active site. In the context of these results, the possible role of Arg42 and Asn178 in a "lock down" mechanism affecting active site access is discussed. In silico substrate docking of enantiomeric substrates has been examined in order to evaluate the enzymes enantioselectivity. Crown Copyright © 2007.
Persistent Identifierhttp://hdl.handle.net/10722/68608
ISSN
2015 Impact Factor: 4.517
2015 SCImago Journal Rankings: 3.002
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorSchmidberger, JWen_HK
dc.contributor.authorWilce, JAen_HK
dc.contributor.authorTsang, JSHen_HK
dc.contributor.authorWilce, MCJen_HK
dc.date.accessioned2010-09-06T06:06:06Z-
dc.date.available2010-09-06T06:06:06Z-
dc.date.issued2007en_HK
dc.identifier.citationJournal Of Molecular Biology, 2007, v. 368 n. 3, p. 706-717en_HK
dc.identifier.issn0022-2836en_HK
dc.identifier.urihttp://hdl.handle.net/10722/68608-
dc.description.abstractDehIVa is a haloacid dehalogenase (EC 3.8.1.2) from the soil and water borne bacterium Burkholderia cepacia MBA4, which belongs to the functionally variable haloacid dehalogenase (HAD) superfamily of enzymes. The haloacid dehalogenases catalyse the removal of halides from haloacids resulting in a hydroxlated product. These enzymes are of interest for their potential to degrade recalcitrant halogenated environmental pollutants and their use in the synthesis of industrial chemicals. The haloacid dehalogenases utilise a nucleophilic attack on the substrate by an aspartic acid residue to form an enzyme-substrate ester bond and concomitantly cleaving of the carbon-halide bond and release of a hydroxylated product following ester hydrolysis. We present the crystal structures of both the substrate-free DehIVa refined to 1.93 Å resolution and DehIVa covalently bound to l-2-monochloropropanoate trapped as a reaction intermediate, refined to 2.7 Å resolution. Electron density consistent with a previously unidentified yet anticipated water molecule in the active site poised to donate its hydroxyl group to the product and its proton to the catalytic Asp11 is evident. It has been unclear how substrate enters the active site of this and related enzymes. The results of normal mode analysis (NMA) are presented and suggest a means whereby the predicted global dynamics of the enzyme allow for entry of the substrate into the active site. In the context of these results, the possible role of Arg42 and Asn178 in a "lock down" mechanism affecting active site access is discussed. In silico substrate docking of enantiomeric substrates has been examined in order to evaluate the enzymes enantioselectivity. Crown Copyright © 2007.en_HK
dc.languageengen_HK
dc.publisherAcademic Press. The Journal's web site is located at http://www.elsevier.com/locate/jmben_HK
dc.relation.ispartofJournal of Molecular Biologyen_HK
dc.subjectαHA dehalogenaseen_HK
dc.subjectdehalogenaseen_HK
dc.subjectHAD superfamilyen_HK
dc.subjectlow barrier hydrogen bonden_HK
dc.subjectnormal mode analysisen_HK
dc.titleCrystal Structures of the Substrate Free-enzyme, and Reaction Intermediate of the HAD Superfamily Member, Haloacid Dehalogenase DehIVa from Burkholderia cepacia MBA4en_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0022-2836&volume=368&spage=706&epage=717&date=2007&atitle=Crystal+structures+of+the+substrate+free-enzyme,+and+reaction+intermediate+of+the+HAD+superfamily+member,+haloacid+dehalogenase+DehIVa+from+Burkholderia+cepacia+MBA4en_HK
dc.identifier.emailTsang, JSH: jshtsang@hku.hken_HK
dc.identifier.authorityTsang, JSH=rp00792en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1016/j.jmb.2007.02.015en_HK
dc.identifier.pmid17368477-
dc.identifier.scopuseid_2-s2.0-34047138335en_HK
dc.identifier.hkuros127426en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-34047138335&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume368en_HK
dc.identifier.issue3en_HK
dc.identifier.spage706en_HK
dc.identifier.epage717en_HK
dc.identifier.isiWOS:000246060200008-
dc.publisher.placeUnited Kingdomen_HK
dc.identifier.scopusauthoridSchmidberger, JW=13407197400en_HK
dc.identifier.scopusauthoridWilce, JA=7004850054en_HK
dc.identifier.scopusauthoridTsang, JSH=7102483508en_HK
dc.identifier.scopusauthoridWilce, MCJ=7003621929en_HK

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