4hup

Structure of ricin A chain bound with N-(N-(pterin-7-yl)carbonylglycyl)-L-phenylalanyl)-L-phenylalanine

spinqualitylabelsall models 4hup, resolution 1.70Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4hup is a 1 chain structure with sequence from Ricinus communis. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.699Å Ligands: 19M, MLA, SO4 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function RICI_RICCO Ricin is highly toxic to animal cells and to a lesser extent to plant cells. The A chain acts as a glycosidase that removes a specific adenine residue from an exposed loop of the 28S rRNA (A4324 in mammals), leading to rRNA breakage. As this loop is involved in elongation factor binding, modified ribosomes are catalytically inactive and unable to support protein synthesis. The A chain can inactivate a few thousand ribosomes per minute, faster than the cell can make new ones. Therefore a single A chain molecule can kill an animal cell. The B chain binds to beta-D-galactopyranoside moieties on cell surface glycoproteins and glycolipids and facilitates the entry into the cell of the A chain; B chains are also responsible for cell agglutination (Lectin activity). Publication Abstract from PubMed Several 7-peptide-substituted pterins were synthesized and tested as competitive active-site inhibitors of ricin toxin A (RTA). Focus began on dipeptide conjugates, and these results further guided the construction of several tripeptide conjugates. The binding of these compounds to RTA was studied via a luminescence-based kinetic assay, as well as through X-ray crystallography. Despite the relatively polar, solvent exposed active site, several hydrophobic interactions, most commonly pi-interactions not predicted by modeling programs, were identified in all of the best-performing inhibitors. Nearly all of these compounds provide IC(50) values in the low micromolar range. Peptide-Conjugated Pterins as Inhibitors of Ricin Toxin A.,Saito R, Pruet JM, Manzano LA, Jasheway K, Monzingo AF, Wiget PA, Kamat I, Anslyn EV, Robertus JD J Med Chem. 2012 Dec 19. PMID:23214944 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Ricin 3D structures

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