Characteristics and DNA-sequence of a cryptic haloalkanoic acid dehalogenase from Agrobacterium tumefaciens RS5.
Agrobacterium tumefaciens RS5 harbors two different hydrolytic haloalkanoic acid dehalogenase genes, one coding for a nonstereospecific enzyme (DhlS5II) and a second for a cryptic L-isomer-specific dehalogenase (DhlS5I). The latter gene was cloned and expressed in Escherichia coli. Biochemical characterization and sequence analysis of dhlS5I shows its membership to the class of the L-isomer-specific hydrolytic dehalogenases. Highest homology of 72% was found to the dehalogenase LdexYL from Pseudomonas sp. YL. Both enzymes share an unusual high temperature optimum of 65 degrees C. Controlled by a vector promoter, high specific dehalogenase activities up to 32 U mg-1 protein were obtained in E. coli, and putatively, owing to its own sigma70-dependent promoter, a constitutive low-level expression of dhlS5I of 0.4 U mg-1 protein was measured.
Köhler
R
R
Department of Microbiology, FB19, University Gesamthochschule Kassel, Heinrich-Plett-Str. 40, D-34109 Kassel, Germany.
Brokamp
A
A
Schwarze
R
R
Reiting
R H
RH
Schmidt
F R
FR
D016960:Agrobacterium tumefaciens / Q000201:enzymology* / Q000235:genetics*; D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D016384:Consensus Sequence; D015870:Gene Expression / Q000235:genetics; D005798:Genes, Bacterial / Q000235:genetics; D006867:Hydrolases / Q000235:genetics*; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA
D006867:Hydrolases; C034507:2-haloacid dehalogenase