Synthesis of Stable Cholesteryl-Polyethylene Glycol-Peptide Conjugates with Non-Disperse Polyethylene Glycol Lengths

Edgar Cristóbal-Lecina; Daniel Pulido; Pau Martin-Malpartida; Maria J Macias; Fernando Albericio; Miriam Royo

doi:10.1021/acsomega.0c00130

Synthesis of Stable Cholesteryl-Polyethylene Glycol-Peptide Conjugates with Non-Disperse Polyethylene Glycol Lengths

ACS Omega. 2020 Mar 6;5(10):5508-5519. doi: 10.1021/acsomega.0c00130. eCollection 2020 Mar 17.

Authors

Edgar Cristóbal-Lecina^{1

2}, Daniel Pulido^{1

2}, Pau Martin-Malpartida^{3

4}, Maria J Macias^{3

4

5}, Fernando Albericio^{1

2

6

7}, Miriam Royo^{1

2}

Affiliations

¹ Department of Surfactants and Nanobiotechnology, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), Jordi Girona 18-26, 08034 Barcelona, Spain.
² Centro de Investigación Biomédica en Red Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), 28029 Madrid, Spain.
³ Institute for Research in Biomedicine (IRB Barcelona), Baldiri i Reixach 10, 08028 Barcelona Spain.
⁴ The Barcelona Institute of Science and Technology (BIST), 08036 Barcelona, Spain.
⁵ ICREA, Passeig Lluis Companys 23, 08010 Barcelona, Spain.
⁶ Department of Inorganic and Organic Chemistry, University of Barcelona, Marti i Franqués 1-11, 08028 Barcelona, Spain.
⁷ School of Chemistry and Physics, University of KwaZulu-Natal, 4041 Durban, South Africa.

Abstract

A method for conjugating cholesterol to peptide ligands through non-disperse polyethylene glycol (ND-PEG) through a non-hydrolysable linkage is described. The iterative addition of tetraethylene glycol macrocyclic sulfate to cholesterol (Chol) renders a family of highly pure well-defined Chol-PEG compounds with different PEG lengths from 4 up to 20 ethylene oxide units, stably linked through an ether bond. The conjugation of these Chol-PEG compounds to the cyclic (RGDfK) peptide though Lys5 side chains generates different lengths of Chol-PEG-RGD conjugates that retain the oligomer purity of the precursors, as analysis by HRMS and NMR has shown. Other derivatives were synthesized with similar results, such as Chol-PEG-OCH₃ and Chol-PEG conjugated to glutathione and Tf1 peptides through maleimide-thiol chemoselective ligation. This method allows the systematic synthesis of highly pure uniform stable Chol-PEGs, circumventing the use of activation groups on each elongation step and thus reducing the number of synthesis steps.