Biochemical characterization of L-carnitine dehydrogenases from Rhizobium sp. and Xanthomonas translucens.
Recently, we obtained two L-carnitine dehydrogenases (CDHs) from soil isolates, Rhizobium sp. (Rs-CDH) and Xanthomonas translucens (Xt-CDH). The respective molecular masses of Rs-CDH and Xt-CDH were approximately 50 kDa and 37 kDa. In this study, the genes encoding both enzymes were cloned. Their primary structures exhibited high identities with those of 3-hydroxyacyl-CoA dehydrogenases. In addition, Rs-CDH had a 180-residue long extra sequence in its C-terminal region. Except for the initial 20 residues, the extra sequence exhibited similarity to thioesterase. The activity of Rs-CDH was affected only slightly by deletion of thioesterase domain, but it was eliminated by the deletion of the whole C-terminal extra sequence. A further deletion experiment indicated that the region of Ala330-Pro335 of Rs-CDH has important functions in catalytic activity. Moreover, based on the deletion experiment on Xt-CDH, the five-residue tail is considered to have a function similar to Ala330-Pro335 of Rs-CDH.
Department of Agricultural, Biological, and Environmental Sciences, Faculty of Agriculture, Tottori University, Tottori, Japan.
Jiro
J
Arima
Akifumi
A
Uesumi
Hitoshi
H
Mitsuzumi
Nobuhiro
N
Mori
D000429:Alcohol Oxidoreductases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D012231:Rhizobium / Q000201:enzymology* / Q000235:genetics; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D014974:Xanthomonas / Q000201:enzymology* / Q000235:genetics
D011993:Recombinant Fusion Proteins; D000429:Alcohol Oxidoreductases; C019842:carnitine dehydrogenase