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DNA determinants important in sequence recognition by Eco RI endonuclease.
The Journal of Biological Chemistry
|December 25, 1981
Summary
Eco RI endonuclease uses specific DNA contacts, including major and minor groove interactions and phosphate backbone connections, to bind its recognition sequence. These interactions exhibit 2-fold symmetry, forming a stable DNA-protein complex.
Area of Science:
- Molecular Biology
- Biochemistry
- Structural Biology
Background:
- Eco RI endonuclease is a key enzyme in DNA manipulation.
- Understanding its DNA binding mechanism is crucial for molecular biology applications.
Purpose of the Study:
- To elucidate the specific DNA contact points of Eco RI endonuclease.
- To investigate the symmetry and structural basis of Eco RI-DNA complex formation.
Main Methods:
- Alkylation interference and protection assays using dimethylsulfate and ethylating agents.
- Analysis of DNA methylation interference patterns.
Main Results:
- Identified specific DNA bases (N7 of dG, N3 of dA) and phosphates involved in Eco RI binding.
- Demonstrated 2-fold symmetry in DNA-protein interactions.
- Showed that methylation of the Eco RI recognition site by the modification enzyme prevents specific alkylation effects.
Conclusions:
- Eco RI endonuclease interacts with at least 10 nucleotide pairs via specific base and phosphate contacts.
- The DNA-protein complex formation is characterized by elements of symmetry.
- Enzyme specificity is maintained through precise recognition of the DNA sequence.