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Crystal structure and function of C-terminal Sau3AI domain
Chun-Yan Xu1, Feng Yu, Si-Jie Xu
1Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China.
Biochimica Et Biophysica Acta
|October 22, 2008
Summary
Sau3AI restriction enzyme
Area of Science:
- Molecular Biology
- Structural Biology
- Enzymology
Background:
- Sau3AI is a type II restriction enzyme recognizing the 5'-GATC-3' DNA sequence.
- Its C-terminal domain (Sau3AI-C) shares structural similarity with the DNA mismatch repair protein MutH.
Purpose of the Study:
- To elucidate the structure and function of the Sau3AI C-terminal domain.
- To understand the role of Sau3AI-C in DNA binding and cleavage.
Main Methods:
- Crystallization of the Sau3AI C-terminal domain (Sau3AI-C).
- Structure determination using Multi-wavelength Anomalous Diffraction (MAD) at 1.9 A resolution.
- Functional analysis of Sau3AI-C for DNA binding and cleavage activity.
Main Results:
- The crystal structure of Sau3AI-C was solved, revealing similarity to MutH.
- Sau3AI-C demonstrated DNA binding capability for one recognition sequence.
- Sau3AI-C exhibited no DNA cleavage activity on its own.
Conclusions:
- Sau3AI functions as a pseudo-dimer, classified as a type IIe restriction enzyme.
- The Sau3AI-C domain acts as an allosteric effector, crucial for DNA binding and cleavage facilitation.
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