Dicarba-closo-dodecaboranes possess thermal and chemical stability as well as a unique three-dimensional structure. Due to their high boron content, carboranes are of particular interest for BNCT (Boron Neutron Capture Therapy). Their incorporation into polypeptide chains enables the preparation of targeted and effective boron delivery systems to tumor cells.
As part of this thesis, we synthesized a homo-bifunctional carborane reagent with two N-hydroxysuccinimide (NHS) ester groups, which served as a linking moiety between peptide chains. Using automated method Fmoc-SPPS (Solid-Phase Peptide Synthesis), we prepared peptides with different amino acid sequences and lengths. We synthesized the polymer structures under various conditions to investigate how different peptide sequences, the reagent-to-peptide ratio, and reaction temperature affect the length of the resulting polymers. The presence of histidine in the vicinity of lysine proved to be crucial for the formation of a stable amide bond between the carborane reagent and the peptide. To form longer polymers without unwanted smearing on the SDS-PAGE gel, the optimal ratio was 1:4 (reagent : peptide) at 50 °C.
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