Linked Life Data

12952988

Source:http://linkedlifedata.com/resource/pubmed/id/12952988

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
46
pubmed:dateCreated
2003-11-10
pubmed:abstractText
Haloalkane dehalogenases are bacterial enzymes capable of carbon-halogen bond cleavage in halogenated compounds. To obtain insights into the mechanism of the haloalkane dehalogenase from Sphingomonas paucimobilis UT26 (LinB), we studied the steady-state and presteady-state kinetics of the conversion of the substrates 1-chlorohexane, chlorocyclohexane, and bromocyclohexane. The results lead to a proposal of a minimal kinetic mechanism consisting of three main steps: (i) substrate binding, (ii) cleavage of the carbon-halogen bond with simultaneous formation of an alkyl-enzyme intermediate, and (iii) hydrolysis of the alkyl-enzyme intermediate. Release of both products, halide and alcohol, is a fast process that was not included in the reaction mechanism as a distinct step. Comparison of the kinetic mechanism of LinB with that of haloalkane dehalogenase DhlA from Xantobacter autotrophicus GJ10 and the haloalkane dehalogenase DhaA from Rhodococcus rhodochrous NCIMB 13064 shows that the overall mechanisms are similar. The main difference is in the rate-limiting step, which is hydrolysis of the alkylenzyme intermediate in LinB, halide release in DhlA, and liberation of an alcohol in DhaA. The occurrence of different rate-limiting steps for three enzymes that belong to the same protein family indicates that extrapolation of this important catalytic property from one enzyme to another can be misleading even for evolutionary closely related proteins. The differences in the rate-limiting step were related to: (i) number and size of the entrance tunnels, (ii) protein flexibility, and (iii) composition of the halide-stabilizing active site residues based on comparison of protein structures.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Nov
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
14
pubmed:volume
278
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
45094-100
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed-meshheading:12952988-Carbon, pubmed-meshheading:12952988-Catalysis, pubmed-meshheading:12952988-Cyclohexanes, pubmed-meshheading:12952988-Dose-Response Relationship, Drug, pubmed-meshheading:12952988-Halogens, pubmed-meshheading:12952988-Hexanes, pubmed-meshheading:12952988-Hydrocarbons, Chlorinated, pubmed-meshheading:12952988-Hydrogen-Ion Concentration, pubmed-meshheading:12952988-Hydrolases, pubmed-meshheading:12952988-Hydrolysis, pubmed-meshheading:12952988-Kinetics, pubmed-meshheading:12952988-Ligands, pubmed-meshheading:12952988-Models, Chemical, pubmed-meshheading:12952988-Models, Molecular, pubmed-meshheading:12952988-Protein Binding, pubmed-meshheading:12952988-Protein Conformation, pubmed-meshheading:12952988-Sphingomonas, pubmed-meshheading:12952988-Temperature, pubmed-meshheading:12952988-Time Factors
pubmed:year
2003
pubmed:articleTitle
Catalytic mechanism of the maloalkane dehalogenase LinB from Sphingomonas paucimobilis UT26.
pubmed:affiliation
National Centre for Biomolecular Research, Masaryk University, Kotlarska 2, 611 37 Brno, Czech Republic.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't