Synthesis and structural characterization of bioactive peptide conjugates using thioether linkage approaches. |
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Authors: | Gbor Mez Marilena Manea Annamria Jakab Bence Kapuvri Szilvia Bsze Gitta Schlosser Michael Przybylski Ferenc Hudecz |
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Institution: | Research Group of Peptide Chemistry, Hungarian Academy of Sciences, E?tv?s L. University, Budapest, Hungary. mezo@szerves.chem.elte.hu |
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Abstract: | Applications of cysteine-insertion and thioether linkage approaches to the preparation of a number of bioactive peptide conjugates are reported. Peptides containing epitopes from (i) herpes simplex virus type 1 glycoprotein D, (ii) a specific N-terminal beta-amyloid epitope recognized by therapeutically active antibodies, and (iii) a GnRH-III peptide from sea lamprey with antitumour activity, were elongated with Cys residues and attached to a chloroacetylated tetratuftsin derivative carrier via a thioether linkage either directly, or by insertion of a spacer. The structures and molecular homogeneity of all the peptide conjugates were ascertained by HPLC, MALDI and electrospray mass spectrometry. The use of a spacer such as an oligoglycine or GFLG-tetrapeptide gave an increased yield in the conjugation reaction and enhanced reaction rates. In the formation of cysteinyl-thioether linkages, it was found that the position of flanking Cys residues markedly influenced the conjugation reaction and the formation of intermolecular epitope disulfide-dimers. C-terminal Cys residues gave thioether conjugates with significantly diminished epitope-dimerization, while Cys at the N-terminal caused rapid disulfide-dimerization, thereby preventing efficient conjugation. |
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Keywords: | peptide conjugates tetratuftsin derivative thioether bond Cys‐peptides HSV epitope peptide β‐amyloid epitope GnRH‐III |
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