Download Mendeley2.8-A crystal structure of a nontoxic type-II ribosome-inactivating protein, ebulin l.
Pascal, J.M., Day, P.J., Monzingo, A.F., Ernst, S.R., Robertus, J.D., Iglesias, R., Perez, Y., Ferreras, J.M., Citores, L., Girbes, T.(2001) Proteins 43: 319-326
- PubMed: 11288182
- DOI: https://doi.org/10.1002/prot.1043
- Primary Citation of Related Structures:
1HWM, 1HWN, 1HWO, 1HWP - PubMed Abstract:
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.
Organizational Affiliation:
Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas 78712, USA.
