Structure–Activity Relationship Studies, SPR Affinity Characterization, and Conformational Analysis of Peptides That Mimic the HNK‐1 Carbohydrate Epitope

Abstract

The design of molecules that mimic biologically relevant glycans is a significant goal for understanding important biological processes and may lead to new therapeutic and diagnostic agents. In this study we focused our attention on the trisaccharide human natural killer cell-1 (HNK-1), considered the antigenic determinant of myelin-associated glycoprotein and the target of clinically relevant auto-antibodies in autoimmune neurological disorders such as IgM monoclonal gammopathy and demyelinating polyneuropathy. We describe a structure-activity relationship study based on surface plasmon resonance binding affinities aimed at the optimization of a peptide that mimics the HNK-1 minimal epitope. We developed a cyclic heptapeptide that shows an affinity of 1.09×10 m for a commercial anti-HNK1 mouse monoclonal antibody. Detailed conformational analysis gave possible explanations for the good affinity displayed by this novel analogue, which was subsequently used as an immunological probe. However, preliminary screening indicates that patients' sera do not specifically recognize this peptide, showing that murine monoclonal antibodies cannot be used as a guide to select immunological probes for the detection of clinically relevant human auto-antibodies.

Sensitizing Staphylococcus aureus to antibacterial agents by decoding and blocking the lipid flippase MprF

“…An N-terminal and a C-terminal cysteine were added to enable cyclization. Biotin was coupled to the peptide via a 4,7,10-trioxa-1,13-tridecanediamine succinic acid (Ttds) linker ( Ieronymaki et al, 2017 ). Cyclization and coupling of linker and biotin were performed by JPT Peptide Technologies.…”

An Optimised Di-Boronate-ChemMatrix Affinity Chromatography to Trap Deoxyfructosylated Peptides as Biomarkers of Glycation

“…These peptides were selected for the following characteristics: amino acid sequence, hydrophobicity, different length (from 4 to 35 amino acids) and post-translational modification (DeoxyFru, Ac, PO 3 H 2 , and Pam). The hexapeptide LSETTI (11) was selected as a previously developed peptide mimicking the HNK1 tri-saccharide epitope [37]. It is interesting to notice that Frolov et al [19] previously reported that the efficiency of the m-aminophenylboronic acid (m-APBA) immobilised on agarose resin to capture Amadori peptides, after digestion of plasma protein from type 2 diabetes, was affected by unspecific recognition of peptide sequences containing several, often neighbouring, hydroxyamino acid residues.…”

SensitizingStaphylococcus aureusto antibacterial host defense by decoding and blocking the lipid flippase MprF

“…An N-terminal and a C-terminal cysteine were added to enable cyclization. Biotin was coupled to the peptide via a 4,7,10-trioxa-1,13-tridecanediamine succinic acid (Ttds)-linker (Ieronymaki, Nuti et al, 2017). Cyclization and coupling of linker and biotin were performed by JPT Peptide Technologies.…”