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Expression, purification, and characterization of thymidylate synthase from Lactococcus lactis
1Department of Biochemistry, University of California, San Francisco 94143.
Summary
Researchers highly expressed and purified thymidylate synthase (TS) from Lactococcus lactis. This provides ample enzyme for studying its structure-function relationships and compensatory changes in catalytic residues.
Area of Science:
- Biochemistry
- Molecular Biology
- Enzymology
Background:
- Thymidylate synthase (TS) is a crucial enzyme in DNA synthesis.
- Understanding TS structure-function relationships is vital for drug development.
- Lactococcus lactis TS offers a unique model for comparative enzymology.
Purpose of the Study:
- To highly express and purify Lactococcus lactis thymidylate synthase (TS).
- To investigate the structure-function relationships of L. lactis TS.
- To explore compensatory amino acid changes in L. lactis TS.
Main Methods:
- High-level expression of the TS gene in Escherichia coli.
- Purification of TS protein using Q-Sepharose and phenyl-Sepharose chromatography.
- 3-dimensional homology modeling to predict amino acid substitutions.
Main Results:
- Successfully purified 140 mg of homogeneous L. lactis TS from 6g of cell pellet.
- Identified altered conserved amino acid residues in L. lactis TS compared to other TS enzymes.
- Predicted covariant amino acid changes that may compensate for altered residues.
Conclusions:
- Large quantities of homogeneous L. lactis TS are now available for further research.
- The study provides a basis for understanding TS structure-function dynamics.
- Predicted compensatory changes warrant experimental validation to confirm their roles.