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Lactose repressor protein: functional properties and structure
1Department of Biochemistry and Cell Biology, Rice University, Houston, Texas 77251, USA.
Progress in Nucleic Acid Research and Molecular Biology
|October 6, 1997
Summary
The lactose repressor protein (LacI) regulates lactose metabolism in E. coli. Its structure, revealed by X-ray crystallography, explains how inducers change its DNA binding, enabling lactose utilization.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- The lactose repressor protein (LacI) is a key genetic regulatory protein in E. coli.
- It controls the expression of genes involved in lactose metabolism by binding to specific DNA operator sequences.
- Understanding LacI's mechanism is crucial for gene regulation studies.
Purpose of the Study:
- To correlate the function of the lactose repressor protein (LacI) with its structure.
- To investigate the impact of inducers on LacI's DNA binding affinity.
- To explore the applications of LacI in gene regulation and mutagenesis studies.
Main Methods:
- Genetic, chemical, and physical studies.
- X-ray crystallography to determine protein structures.
- Analysis of mutant phenotypes and structures.
Main Results:
- Inducer binding causes a conformational change in LacI, reducing its affinity for operator DNA.
- This conformational change leads to the synthesis of mRNA for lactose utilization.
- Structural data complements existing phenotypic data for numerous LacI mutants.
Conclusions:
- The structure of LacI provides a physical basis for understanding its regulatory function and structure-function relationships.
- LacI serves as a valuable tool in both prokaryotic and eukaryotic gene expression studies.
- Further studies on LacI mutants can elucidate specific aspects of its structure and function.