Identification, affinity characterisation and biological interactions of lectin-like peptide-carbohydrate complexes derived from human TNF-α using high-resolution mass spectrometry

• Published in: Journal of peptide science 2007-12, Vol.13 (12), p.803-810
• Main Authors: Marquardt, Andreas, Bernevic, Bogdan, Przybylski, Michael
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Binding, Competitive; Carbohydrate Conformation; Carbohydrates - chemical synthesis; Carbohydrates - chemistry; Carbohydrates - pharmacology; cyclic TIP peptide-carbohydrate complexes; Disaccharides - chemistry; Disulfides - chemistry; ESI-FTICR mass spectrometry; glycoprotein interactions; Humans; lectin-like peptide domain; Lectins - chemical synthesis; Lectins - chemistry; Lectins - pharmacology; Molecular Sequence Data; Peptides, Cyclic - chemical synthesis; Peptides, Cyclic - chemistry; Peptides, Cyclic - pharmacology; Protein Conformation; proteolytic stability; Spectrometry, Mass, Electrospray Ionization - methods; Spectroscopy, Fourier Transform Infrared - methods; TNF-α; Tumor Necrosis Factor-alpha - chemistry
• ISSN: 1075-2617; 1099-1387
• DOI: 10.1002/psc.902

A cyclic disulfide heptadecapeptide (TIP17ox; 2) derived from the lectin‐like 17‐amino acid domain of human tumor necrosis factor‐α [TNF‐α (100–116)] was synthesised and demonstrated to bind specifically to N,N‐diacetylchitobiose, a disaccharide present in many glycan structures of glycoproteins. Although the TIP domain forms a loop structure in the native TNF‐α protein, we show in this study by high‐resolution ESI‐FTICR mass spectrometry that a homologous linear heptadecapeptide (TIP17rd; 1) binds with comparable affinity to chitobiose, suggesting that cyclisation is not essential for carbohydrate binding. ESI‐FTICR‐MS was used as an efficient tool for the direct molecular characterisation of TIP peptide–carbohydrate complexes. The specific binding of the TNF‐TIP domain to chitobiose and other carbohydrate motifs in glycoproteins may explain the high proteolytic stability of these peptides in biological fluids. A considerably higher proteolytic stability in human plasma was found by mass spectrometric analysis for the cyclic TIP peptide 2, compared to the linear peptide 1. Furthermore, affinity‐proteomics studies using immobilised cyclic TIP peptide 2 provided the identification of specific interacting glycoproteins in plasma. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd.