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Published on: March 8, 2018
Peptide-conjugated pterins as inhibitors of ricin toxin A
Ryota Saito1, Jeff M Pruet, Lawrence A Manzano
1Department of Chemistry, Toho University, 2-2-1 Miyama, Funabashi 274-8510, Japan. anslyn@austin.utexas.edu
Abstract:
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 π-interactions not predicted by modeling programs, were identified in all of the best-performing inhibitors. Nearly all of these compounds provide IC₅₀ values in the low micromolar range.
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