Title
CXC-Mediated Cellular Uptake of Miniproteins: Forsaking “Arginine Magic”
Author
Xiaoting Meng, Tao Li, Yibing Zhao, Chuanliu Wu
Year
2018
Journal
ACS Chemical Biology
Abstract
Miniproteins are lying between larger biologics and small molecules in size, and presumably possess the advantages of both, which represent an expanding class of promising scaffolds for the design of affinity reagents, enzymes and therapeutics. Conventional strategies to promote cellular uptake of miniproteins rely on extensive grafting or embedding of arginine residues. However, the requirement of using cationic arginines would cause problems to the modified miniproteins, e.g., low solubility in solutions (proneness of aggregation) and potential toxicity, which is an open secret in the peptide and protein communities. In this work, we report that the cell-permeability of cationic miniproteins can be further markedly increased through appending a magic CXC motif, which takes advantage of thiol-disulfide exchanges on the cell surface. More importantly, we serendipitously discovered that ultra-high cell permeability of the CXC-appended miniproteins can still be preserved when the embedded arginines are all substituted with lysine residues, indicating that the “arginine magic” essential to almost all cell-permeable peptides and (mini)proteins is not required for the CXC-mediated cellular uptake. This finding provides a new avenue for designing highly cell-permeable miniproteins without compromise of potential toxicity and stability arising from arginine embedding or grafting.
Instrument
J-810
Keywords
Circular dichroism, Secondary structure, Biochemistry