A small peptide mimic of the Grb2-SH2 domain, which was previously prepared through the template-assisted click approach and exhibited selective A431 tumor growth inhibition both in vitro and in vivo, was further elaborated on to enhance the interaction with target phosphorylated proteins. A conformationally fixed analog was efficiently synthesized by solid-supported ring-closing metathesis and Cu(i)/His-mediated self-activating Huisgen [3+2] cycloadditon as the key steps, and exhibited a 10-fold enhanced affinity to a phosphorylated peptide, a truncated peptide analog of the Grb2-SH2-interacting phosphoproteins. A stronger interaction with the target phosphorylated proteins gave this cyclic analog cytotoxic activity in A431 cells.
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http://dx.doi.org/10.1039/c3mb25462c | DOI Listing |
bioRxiv
June 2024
Department of Biochemistry and Biophysics, UNC Chapel Hill School of Medicine; Chapel Hill, NC 27516, USA.
Adaptor protein complex 3 (AP-3) mediates cargo sorting from endosomes to lysosomes and lysosome-related organelles. Recently, it was shown that AP-3 is in a constitutively open, active conformation compared to the related AP-1 and AP-2 coat complexes, which are inactive until undergoing large conformational changes upon membrane recruitment. How AP-3 is regulated is therefore an open question.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
February 2024
Department of Chemistry, Rutgers University, 73 Warren Street, Newark, NJ 07102, USA.
IMes (IMes=1,3-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene) and IPr (IPr=1,3- bis(2,6-diisopropylphenyl)imidazol-2-ylidene) represent by far the most frequently used N-heterocyclic carbene ligands in homogeneous catalysis, however, despite numerous advantages, these ligands are limited by the lack of steric flexibility of catalytic pockets. We report a new class of unique unsymmetrical N-heterocyclic carbene ligands that are characterized by freely-rotatable N-aromatic wingtips in the imidazol-2-ylidene architecture. The combination of rotatable N-CH Ar bond with conformationally-fixed N-Ar linkage results in a highly modular ligand topology, entering the range of geometries inaccessible to IMes and IPr.
View Article and Find Full Text PDFChem Sci
October 2023
Yusuf Hamied Department of Chemistry, University of Cambridge Cambridge CB2 1EW UK
Conformationally well-defined supramolecular complexes that can be studied in different solvents provide a platform for separating and quantifying free energy contributions due to functional group interactions and desolvation. Here 1:1 complexes formed between four different calix[4]pyrrole receptors and eleven different pyridine -oxide guests have been used to dissect the factors that govern aromatic interactions with heterocycles in water and in chloroform solution. H NMR spectroscopy shows that the three-dimensional structures of the complexes are fixed by four H-bonding interactions between the pyrrole donors at the bottom of the receptor and the -oxide acceptor on the guest, locking the geometrical arrangement of interacting functional groups in the binding pocket at the other end of the receptor.
View Article and Find Full Text PDFOrg Lett
November 2023
Department of Life Sciences and Technology, Tokyo Institute of Technology, 4259 Nagatsuta-cho, Midori-ku, Yokohama Kanagawa 226-8501, Japan.
A cyclic nucleoside has been designed and synthesized to serve as a conformationally fixed building block for the development of functional oligonucleotides. The bridge was introduced between the nucleobase and the 5'-position to fix the rotation around the C4'-C5' bond, the base orientation, and the sugar puckering all at once. The 13-membered cyclic structure was introduced using a sulfonamide linkage, which retains an N-H group that can be used to attach an additional nucleoside moiety.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
July 2023
Centro Singular de Investigación en Química Biolóxica e Materiais Moleculares (CiQUS) and Departamento de Química Orgánica, Universidade de Santiago de Compostela, E-15782, Santiago de Compostela, Spain.
Helix inversion in chiral dynamic helical polymers is usually achieved by conformational changes at the pendant groups induced through external stimuli. Herein, a different mechanism of helix inversion in poly(phenylacetylene)s (PPAs) is presented, based on the activation/deactivation of supramolecular interactions. We prepared poly[(allenylethynylenephenylene)acetylene]s (PAEPAs) in which the pendant groups are conformationally locked chiral allenes.
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