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Binding site for fungal beta-lactone hymeglusin on cytosolic 3-hydroxy-3-methylglutaryl coenzyme A synthase
- Source :
- Biochimica et biophysica acta. 1636(1)
- Publication Year :
- 2003
-
Abstract
- We studied the molecular mechanism through which the fungal beta-lactone, hymeglusin, potently and specifically inhibits 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) synthase. [(14)C]Hymeglusin covalently bound to purified rat liver and to recombinant hamster cytosolic HMG-CoA synthases. The enzyme activity was completely inhibited at a binding ratio of 1.6-2.0 mol [(14)C]hymeglusin/mol HMG-CoA synthase. Incubating the enzyme with 2 mM iodoacetamide (IAA) or 2 mM N-ethylmaleimide (NEM) but not with 1.0 mM diisopropyl fluorophosphates (DFP) completely inhibited the binding, suggesting that hymeglusin binds to a Cys residue of HMG-CoA synthase. Recombinant hamster HMG-CoA synthase labeled with [(3)H]hymeglusin was digested with V8 protease, and the [(3)H]peptide was purified by high performance liquid chromatography (HPLC). The sequence of the peptide was Ser-Gly-Asn-Thr-Asp-Ile-Glu-Gly-Ile-Asp-Thr-Thr-Asn-Ala-[(3)H]hymeglusyl Cys-Tyr-Gly-Gly-Thr-Ala-Ala-Val-Phe-Asn-Ala-Val-Asn-, which corresponds to the active site sequence (from Ser 115 to Asn 141) of hamster HMG-CoA synthase. These findings showed that hymeglusin inhibits hamster cytosolic HMG-CoA synthase by covalently modifying the active Cys 129 residue of the enzyme.
- Subjects :
- Hydroxymethylglutaryl-CoA Synthase
Molecular Sequence Data
Hamster
Peptide
Tritium
chemistry.chemical_compound
Lactones
Cytosol
Cricetinae
Coenzyme A Ligases
Endopeptidases
Animals
Amino Acid Sequence
Carbon Radioisotopes
Binding site
Enzyme Inhibitors
Molecular Biology
chemistry.chemical_classification
Binding Sites
biology
ATP synthase
Fungi
Active site
Cell Biology
Molecular biology
Enzyme assay
Peptide Fragments
Recombinant Proteins
Rats
Enzyme
chemistry
Biochemistry
Liver
biology.protein
Iodoacetamide
Fatty Acids, Unsaturated
Cystine
Sequence Alignment
Subjects
Details
- ISSN :
- 00063002
- Volume :
- 1636
- Issue :
- 1
- Database :
- OpenAIRE
- Journal :
- Biochimica et biophysica acta
- Accession number :
- edsair.doi.dedup.....1227cca6fdd1747944398da64cc809e9