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Reconstructing the Discontinuous and Conformational β1/β3‐Loop Binding Site on hFSH/hCG by Using Highly Constrained Multicyclic Peptides
Author(s) -
Smeenk Linde E. J.,
TimmersParohi Drohpatie,
Benschop Joris J.,
Puijk Wouter C.,
Hiemstra Henk,
van Maarseveen Jan H.,
Timmerman Peter
Publication year - 2015
Publication title -
chembiochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.05
H-Index - 126
eISSN - 1439-7633
pISSN - 1439-4227
DOI - 10.1002/cbic.201402540
Subject(s) - chemistry , peptide , cyclic peptide , stereochemistry , binding site , disulfide bond , oxime , covalent bond , biochemistry , organic chemistry
Making peptide‐based molecules that mimic functional interaction sites on proteins remains a challenge in biomedical sciences. Here, we present a robust technology for the covalent assembly of highly constrained and discontinuous binding site mimics, the potential of which is exemplified for structurally complex binding sites on the “Cys‐knot” proteins hFSH and hCG. Peptidic structures were assembled by Ar(CH 2 Br) 2 ‐promoted peptide cyclizations, combined with oxime ligation and disulfide formation. The technology allows unprotected side chain groups and is applicable to peptides of different lengths and nature. A tetracyclic FSH mimic was constructed, showing >600‐fold improved binding compared to linear or monocyclic controls. Binding of a tricyclic hCG mimic to anti‐hCG mAb 8G5 was identical to hCG itself (IC 50 =260 vs. 470 p M ), whereas this mimic displayed an IC 50 value of 149 n M for mAb 3468, an hCG‐neutralizing antibody with undetectable binding to either linear or monocyclic controls.