Binding of adenine to Stx2, the protein toxin from Escherichia coli O157:H7
- Group in Protein Structure and Function, Department of Biochemistry, University of Alberta, Edmonton AB T6G 2H7 (Canada)
- Department of Medical Microbiology and Immunology, University of Alberta, Edmonton AB T6G 2H7 (Canada)
- Department of Microbiology and Infectious Diseases, University of Calgary, 3330 Hospital Drive NW, Calgary AB T2N 4N1 (Canada)
Crystals of Stx2 were grown in the presence of adenosine and adenine. In both cases, the resulting electron density showed only adenine bound at the active site of the A subunit, proving that the holotoxin is an active N-glycosidase. Stx2 is a protein toxin whose catalytic subunit acts as an N-glycosidase to depurinate a specific adenine base from 28S rRNA. In the holotoxin, the catalytic portion, A1, is linked to the rest of the A subunit, A2, and A2 interacts with the pentameric ring formed by the five B subunits. In order to test whether the holotoxin is active as an N-glycosidase, Stx2 was crystallized in the presence of adenosine and adenine. The crystals diffracted to ∼1.8 Å and showed clear electron density for adenine in the active site. Adenosine had been cleaved, proving that Stx2 is an active N-glycosidase. While the holotoxin is active against small substrates, it would be expected that the B subunits would interfere with the binding of the 28S rRNA.
- OSTI ID:
- 22360212
- Journal Information:
- Acta Crystallographica. Section F, Vol. 62, Issue Pt 7; Other Information: PMCID: PMC2242964; PMID: 16820678; PUBLISHER-ID: vr5058; OAI: oai:pubmedcentral.nih.gov:2242964; Copyright (c) International Union of Crystallography 2006; Country of input: International Atomic Energy Agency (IAEA); ISSN 1744-3091
- Country of Publication:
- United Kingdom
- Language:
- English
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