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Crystallization of GreA, a transcript cleavage factor from Escherichia coli
S A Darst1, C E Stebbins, S Borukhov
1Rockefeller University, New York, NY 10021.
Journal of Molecular Biology
|September 30, 1994
Summary
The GreA protein from Escherichia coli, essential for RNA polymerase function, has been crystallized. This structural study provides insights into transcript cleavage mechanisms.
Area of Science:
- Molecular Biology
- Structural Biology
- Biochemistry
Background:
- GreA protein from Escherichia coli plays a crucial role in RNA polymerase function.
- It induces cleavage of nascent transcripts, releasing the 3'-terminal fragment.
Purpose of the Study:
- To obtain high-resolution crystals of the GreA protein.
- To facilitate structural analysis of GreA for understanding its mechanism.
Main Methods:
- Crystallization of GreA using polyethylene glycol 4000, 2-propanol, and sodium citrate (pH 5.6).
- A novel seeding procedure was employed for crystal propagation.
- X-ray diffraction data were collected to beyond 2 Å resolution.
Main Results:
- Orthorhombic space group P2(1)2(1)2(1) was determined for the GreA crystals.
- Unit cell dimensions: a = 101.7 Å, b = 42.22 Å, c = 40.05 Å.
- One molecule of GreA was found in the asymmetric unit.
Conclusions:
- Successfully obtained well-diffracting GreA crystals.
- The structural data will aid in elucidating the mechanism of transcript cleavage by GreA.