Open AccessCellular Uptake and Cytosolic Delivery of a Cyclic Cystine Knot Scaffold
Author(s) -
Huawu Yin,
YenHua Huang,
Kirsten Deprey,
Nicholas D. Condon,
Joshua A. Kritzer,
David J. Craik,
Conan K. Wang
Publication year - 2020
Publication title -
acs chemical biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.899
H-Index - 111
eISSN - 1554-8937
pISSN - 1554-8929
DOI - 10.1021/acschembio.0c00297
Subject(s) - cytosol , intracellular , biochemistry , chemistry , biophysics , microbiology and biotechnology , peptide , scaffold , biology , enzyme , medicine , biomedical engineering
Cyclotides are macrocyclic peptides with exceptionally stable structures and have been reported to penetrate cells, making them promising scaffolds for the delivery of inhibitory peptides to target intracellular proteins. However, their cellular uptake and cytosolic localization have been poorly understood until now, which has limited their therapeutic potential. In this study, the recently developed chloroalkane penetration assay was combined with established assays to characterize the cellular uptake and cytosolic delivery of the prototypic cyclotide, kalata B1. We show that kalata B1 enters the cytosol at low efficiency. A structure-activity study of residues in loop 6 showed that some modifications, such as increasing cationic residue content, did not affect delivery efficiency, whereas others, including introducing a single hydrophobic amino acid, did significantly improve cytosolic delivery. Our results provide a foundation for the further development of a structurally unique class of scaffolds for the delivery of therapeutic cargoes into cells.