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Domain organization and a protease-sensitive loop in eukaryotic ornithine decarboxylase
A L Osterman1, D V Lueder, M Quick
1Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas 75235, USA.
Biochemistry
|October 17, 1995
Summary
Trypanosoma brucei ornithine decarboxylase can be reconstituted from two coexpressed peptides, forming an active enzyme. This reconstitution reveals the enzyme
Area of Science:
- Biochemistry
- Molecular Biology
- Parasitology
Background:
- Trypanosoma brucei causes African sleeping sickness.
- Ornithine decarboxylase (ODC) is a key enzyme in polyamine synthesis.
- Understanding T. brucei ODC structure and function is crucial for drug development.
Purpose of the Study:
- To reconstitute and characterize Trypanosoma brucei ornithine decarboxylase (T. brucei ODC) from coexpressed polypeptides.
- To investigate the domain organization and active site of T. brucei ODC.
- To identify potential drug targets for treating African sleeping sickness.
Main Methods:
- Coexpression of N- and C-terminal T. brucei ODC polypeptides in E. coli.
- Purification and kinetic analysis of the reconstituted enzyme.
- Limited proteolysis and chimeric enzyme analysis to map functional regions.
Main Results:
- Reconstituted T. brucei ODC from coexpressed peptides is fully active and kinetically identical to the wild-type enzyme.
- The enzyme appears to have two structural domains with a boundary around amino acid 305.
- A surface loop (amino acids 160-170) and substrate binding determinants were identified.
Conclusions:
- T. brucei ODC is organized into two distinct structural domains.
- The N-terminal domain contains critical residues for enzymatic activity and substrate binding.
- The study provides insights into T. brucei ODC structure for potential therapeutic interventions.