1qnu
From Proteopedia
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SHIGA-LIKE TOXIN I B SUBUNIT COMPLEXED WITH THE BRIDGED-STARFISH INHIBITOR
Overview
The diseases caused by Shiga and cholera toxins account for the loss of, millions of lives each year. Both belong to the clinically significant, subset of bacterial AB5 toxins consisting of an enzymatically active A, subunit that gains entry to susceptible mammalian cells after, oligosaccharide recognition by the B5 homopentamer. Therapies might target, the obligatory oligosaccharide-toxin recognition event, but the low, intrinsic affinity of carbohydrate-protein interactions hampers the, development of low-molecular-weight inhibitors. The toxins circumvent low, affinity by binding simultaneously to five or more cell-surface, carbohydrates. Here we demonstrate the use of the crystal structure of the, B5 subunit of Escherichia coli O157:H7 Shiga-like toxin I (SLT-I) in, complex with an analogue of its carbohydrate receptor to design an, oligovalent, water-soluble carbohydrate ligand (named STARFISH), with, subnanomolar inhibitory activity. The in vitro inhibitory activity is, 1-10-million-fold higher than that of univalent ligands and is by far the, highest molar activity of any inhibitor yet reported for Shiga-like toxins, I and II. Crystallography of the STARFISH/Shiga-like toxin I complex, explains this activity. Two trisaccharide receptors at the tips of each of, five spacer arms simultaneously engage all five B subunits of two toxin, molecules.
About this Structure
1QNU is a Single protein structure of sequence from Bacteriophage h30, bacteriophaurce 3 with EMB and MEC as ligands. Full crystallographic information is available from OCA.
Reference
Shiga-like toxins are neutralized by tailored multivalent carbohydrate ligands., Kitov PI, Sadowska JM, Mulvey G, Armstrong GD, Ling H, Pannu NS, Read RJ, Bundle DR, Nature. 2000 Feb 10;403(6770):669-72. PMID:10688205
Page seeded by OCA on Wed Nov 21 00:50:12 2007
