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Zn(II)-free dimethylargininase-1 (DDAH-1) is inhibited upon specific Cys-S-nitrosylation.

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  • 2002-11-21
Published in:
  • The Journal of biological chemistry. - 2003
Amidohydrolases
Amino Acid Sequence
Animals
Binding Sites
Brain
Cattle
Cysteine
Hot Temperature
Integrins
Kinetics
Ligands
Mammals
Models, Molecular
Molecular Sequence Data
Nitric Oxide
Nitrosation
Peptide Fragments
Protein Structure, Secondary
Pseudomonas aeruginosa
Recombinant Proteins
Sequence Alignment
Sequence Homology, Amino Acid
Thermodynamics
Zinc
English The endogenous nitric oxide synthase inhibitors L-N(omega)-methylarginine and L-N(omega),N(omega)-dimethylarginine are catabolized by the enzyme dimethylargininase. Dimethylargininase-1 from bovine brain contains one tightly bound Zn(II) coordinated by two cysteine sulfur and two lighter ligands. Activity measurements showed that only the apo-enzyme is active and that the holo-enzyme is activated by zinc removal. In this work, the effect of NO on dimethylargininase-1 structure and its activity was investigated using 2-(N,N-dimethylamino)-diazenolate-2-oxide as an NO source. The results showed that whereas the holo-form was resistant to S-nitrosylation, the apo-form could be modified. The results of absorption spectroscopy, mass spectrometry, and fluorometric S-NO quantification revealed that two of five cysteine residues reacted with NO yielding cysteine-S-NO. The modification reaction is specific, because by liquid chromatography/mass spectrometry experiments of digested S-NO-dimethylargininase-1, cysteines 221 and 273 could be identified as cysteine-NO. Because Zn(II) protects the enzyme against nitrosation, it is suggested that both cysteines are involved in metal binding. However, specific cysteine-S-NO formation occurred in the absence of a characteristic sequence motif. Based on a structural model of dimethylargininase-1, the activation of both cysteines may be accomplished by the close proximity of charged residues in the tertiary structure of the enzyme.
Language
  • English
Open access status
bronze
Identifiers
Persistent URL
https://folia.unifr.ch/global/documents/118867
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