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From Proteopedia
EBULIN COMPLEXED WITH PTEROIC ACID, TRIGONAL CRYSTAL FORM
Overview
Ebulin l is a type-II ribosome-inactivating protein (RIP) isolated from the leaves of Sambucus ebulus L. As with other type-II RIP, ebulin is a disulfide-linked heterodimer composed of a toxic A chain and a galactoside-specific lectin B chain. A normal level of ribosome-inactivating N-glycosidase activity, characteristic of the A chain of type-II RIP, has been demonstrated for ebulin l. However, ebulin is considered a nontoxic type-II RIP due to a reduced cytotoxicity on whole cells and animals as compared with other toxic type-II RIP like ricin. The molecular cloning, amino acid sequence, and the crystal structure of ebulin l are presented and compared with ricin. Ebulin l is shown to bind an A-chain substrate analogue, pteroic acid, in the same manner as ricin. The galactoside-binding ability of ebulin l is demonstrated crystallographically with a complex of the B chain with galactose and with lactose. The negligible cytotoxicity of ebulin l is apparently due to a reduced affinity for galactosides. An altered mode of galactoside binding in the 2gamma subdomain of the lectin B chain primarily causes the reduced affinity.
About this Structure
Full crystallographic information is available from OCA.
Reference
2.8-A crystal structure of a nontoxic type-II ribosome-inactivating protein, ebulin l., Pascal JM, Day PJ, Monzingo AF, Ernst SR, Robertus JD, Iglesias R, Perez Y, Ferreras JM, Citores L, Girbes T, Proteins. 2001 May 15;43(3):319-26. PMID:11288182 Page seeded by OCA on Fri May 2 19:18:12 2008
