2ga4
From Proteopedia
Stx2 with adenine
Structural highlights
Function[STXA_BP933] The A subunit is responsible for inhibiting protein synthesis through the catalytic inactivation of 60S ribosomal subunits. After endocytosis, the A subunit is cleaved by furin in two fragments, A1 and A2: A1 is the catalytically active fragment, and A2 is essential for holotoxin assembly with the B subunits. [STXB_BP933] The B subunit is responsible for the binding of the holotoxin to specific receptors on the target cell surface, such as globotriaosylceramide (Gb3) in human intestinal microvilli. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedStx2 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 approximately 1.8 angstroms 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. Binding of adenine to Stx2, the protein toxin from Escherichia coli O157:H7.,Fraser ME, Cherney MM, Marcato P, Mulvey GL, Armstrong GD, James MN Acta Crystallogr Sect F Struct Biol Cryst Commun. 2006 Jul 1;62(Pt, 7):627-30. Epub 2006 Jun 26. PMID:16820678[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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