Design of Monodisperse and Well‐Defined Polypeptide‐Based Polyvalent Inhibitors of Anthrax Toxin

Abstract

The design of polyvalent molecules, presenting multiple copies of a specific ligand, represents a promising strategy to inhibit pathogens and toxins. The ability to control independently the valency and the spacing between ligands would be valuable for elucidating structure-activity relationships and for designing potent polyvalent molecules. To that end, we designed monodisperse polypeptide-based polyvalent inhibitors of anthrax toxin in which multiple copies of an inhibitory toxin-binding peptide were separated by flexible peptide linkers. By tuning the valency and linker length, we designed polyvalent inhibitors that were over four orders of magnitude more potent than the corresponding monovalent ligands. This strategy for the rational design of monodisperse polyvalent molecules may not only be broadly applicable for the inhibition of toxins and pathogens, but also for controlling the nanoscale organization of cellular receptors to regulate signaling and stem cell fate.

Discovery of Stable and Selective Antibody Mimetics from Combinatorial Libraries of Polyvalent, Loop-Functionalized Peptoid Nanosheets

“…After scale-up, we examined the consistency of (PA63)7 binding specificity to the L034 nanosheet by the FRET assay and by fluorescence microscopy. As a positive control, we created a nanosheet that displays a loop containing a known (PA63)7 binding motif composed of a peptide hexamer, TYWWLD, previously discovered by phage-display methods 30,31 (Fig. 3d).…”

Multivalent Inhibitors of Channel-Forming Bacterial Toxins

“…Instead of a pNAS backbone, Joshi et al used activated poly-L-glutamic acid to conjugate HTSTYWWLDGAP peptide copies, and reported IC 50 values of 20 nM per-peptide basis, which were comparable to the polyacrylamide-based inhibitors (Joshi et al 2006). More recently instead of using the peptide decorated polymeric molecules, the group synthesized polypeptide repeats to interpose multiple instances of modified inhibitory HTSTYWWLDGAP (LIG) peptides with flexible peptide linkers in the sequence of SE[LIG-(SE)m]n to assure optimal linker length, flexibility, and ligand density (Patke et al 2014). Guided by molecular dynamics simulation data, the authors created and tested a range of monodisperse candidate inhibitors with (H) 10 -SE[LIG(SE) 5 ] 7 compound made of decahistidine tag that aids in the purification of the polypeptides, five sequential repeats of serine and glutamic acid, and seven HTSTYWWLDGAP repeats.…”

Recent Advances in Engineering Polyvalent Biological Interactions

“…We recently designed and synthesized a polyvalent inhibitor of anthrax toxin where multiple instances of an inhibitory toxin-binding peptide were separated by flexible peptide linkers (Figure 1 ). 16 By independently controlling the valency and linker length, we elucidated key structure–activity relationships of the inhibitor. At the optimal conditions, the designed polyvalent inhibitors were over 4 orders of magnitude more potent than the corresponding monovalent ligands.…”

“…(B) Ribbon diagram for polypeptide inhibitor (H) 10 -SE[LIG-(SE) 5 ] 4 . Reproduced with permission from John Wiley and Sons, Inc. 16 Copyright 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.…”

“…Often the dissociation constant of a ligand can be improved, that is, decreased, from the micromolar to the nanomolar range by using polyvalency. 16 This attribute makes polyvalency especially apt for selective targeting. Superselectivity is the phenomenon where the adsorption of a polymer/polyvalent molecule on a surface increases faster than linearly with the density of surface binding sites.…”