Characterization of wild-type and mutants of recombinant human GTP cyclohydrolase I: Relationship to etiology of dopa-responsive dystonia

Takahiro Suzuki, Tamae Oe, Hidehito Inagaki, Toshiharu Nagatsu, Hiroshi Ichinose

Research output: Contribution to journalArticle

41 Citations (Scopus)

Abstract

To explore the molecular etiology of two disorders caused by a defect in GTP cyclohydrolase I - hereditary progressive dystonia with marked diurnal fluctuation (HPD), also known as dopa-responsive dystonia (DRD), and autosomal recessive GTP cyclohydrolase I deficiency - we purified and analyzed recombinant human wild-type and mutant GTP cyclohydrolase I proteins expressed in Escherichia coli. Mutant proteins showed very low enzyme activities, and some mutants were eluted at a delayed volume on gel filtration compared with the recombinant wild-type. Next, we examined the GTP cyclohydrolase I protein amount by western blot analysis in phytohemagglutinin-stimulated mononuclear blood cells from HPD/DRD patients. We found a great reduction in the amount of the enzyme protein not only in one patient who had a frameshift mutation, but also in an HPD/DRD patient who had a missense mutation. These results suggest that a dominant-negative effect of chimeric protein composed of wild-type and mutant subunits is unlikely as a cause of the reduced enzyme activity in HPD/DRD patients. We suggest that reduction of the amount of the enzyme protein, which is independent of the mutation type, could be a reason for the dominant inheritance in HPD/DRD.

Original languageEnglish
Pages (from-to)2510-2516
Number of pages7
JournalJournal of Neurochemistry
Volume73
Issue number6
DOIs
Publication statusPublished - 29-11-1999

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GTP Cyclohydrolase
Dihydroxyphenylalanine
Enzyme activity
Enzymes
Proteins
Frameshift Mutation
Phytohemagglutinins
Missense Mutation
Mutant Proteins
Escherichia coli
Gel Chromatography
Blood Cells
Blood
Western Blotting
Gels
Cells
Dopa-Responsive Dystonia
Defects
Mutation

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Cellular and Molecular Neuroscience

Cite this

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title = "Characterization of wild-type and mutants of recombinant human GTP cyclohydrolase I: Relationship to etiology of dopa-responsive dystonia",
abstract = "To explore the molecular etiology of two disorders caused by a defect in GTP cyclohydrolase I - hereditary progressive dystonia with marked diurnal fluctuation (HPD), also known as dopa-responsive dystonia (DRD), and autosomal recessive GTP cyclohydrolase I deficiency - we purified and analyzed recombinant human wild-type and mutant GTP cyclohydrolase I proteins expressed in Escherichia coli. Mutant proteins showed very low enzyme activities, and some mutants were eluted at a delayed volume on gel filtration compared with the recombinant wild-type. Next, we examined the GTP cyclohydrolase I protein amount by western blot analysis in phytohemagglutinin-stimulated mononuclear blood cells from HPD/DRD patients. We found a great reduction in the amount of the enzyme protein not only in one patient who had a frameshift mutation, but also in an HPD/DRD patient who had a missense mutation. These results suggest that a dominant-negative effect of chimeric protein composed of wild-type and mutant subunits is unlikely as a cause of the reduced enzyme activity in HPD/DRD patients. We suggest that reduction of the amount of the enzyme protein, which is independent of the mutation type, could be a reason for the dominant inheritance in HPD/DRD.",
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Characterization of wild-type and mutants of recombinant human GTP cyclohydrolase I : Relationship to etiology of dopa-responsive dystonia. / Suzuki, Takahiro; Oe, Tamae; Inagaki, Hidehito; Nagatsu, Toshiharu; Ichinose, Hiroshi.

In: Journal of Neurochemistry, Vol. 73, No. 6, 29.11.1999, p. 2510-2516.

Research output: Contribution to journalArticle

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T1 - Characterization of wild-type and mutants of recombinant human GTP cyclohydrolase I

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AU - Suzuki, Takahiro

AU - Oe, Tamae

AU - Inagaki, Hidehito

AU - Nagatsu, Toshiharu

AU - Ichinose, Hiroshi

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