Calorimetric Analysis of the Interplay between Synthetic Tn Antigen-Presenting MUC1 Glycopeptides and Human Macrophage Galactose-Type Lectin

Beckwith, Donella M.; FitzGerald, Forrest G.; Benavente, Maria C. Rodriguez; Mercer, Elizabeth R.; Ludwig, Anna-Kristin; Michalak, Malwina; Kaltner, Herbert; Kopitz, Jürgen; Gabius, Hans-Joachim und Cudic, Mare (2021): Calorimetric Analysis of the Interplay between Synthetic Tn Antigen-Presenting MUC1 Glycopeptides and Human Macrophage Galactose-Type Lectin. In: Biochemistry, Bd. 60, Nr. 7: S. 547-558

Abstract

Human macrophage galactose-type lectin (hMGL, HML, CD301, CLEC10A), a C-type lectin expressed by dendritic cells and macrophages, is a receptor for N-acetylgalactosamine alpha-linked to serine/threonine residues (Tn antigen, CD175) and its alpha 2,6-sialylated derivative (sTn, CD175s). Because these two epitopes are among malignant cell glycan displays, particularly when presented by mucin-1 (MUC1), assessing the influence of the site and frequency of glycosylation on lectin recognition will identify determinants governing this interplay. Thus, chemical synthesis of the tandem-repeat O-glycan acceptor region of MUC1 and site-specific threonine glycosylation in all permutations were carried out. Isothermal titration calorimetry (ITC) analysis of the binding of hMGL to this library of MUC1 glycopeptides revealed an enthalpy-driven process and an affinity enhancement of an order of magnitude with an increasing glycan count from 6-8 mu M for monoglycosylated peptides to 0.6 mu M for triglycosylated peptide. ITC measurements performed in D2O permitted further exploration of the solvation dynamics during binding. A shift in enthalpy-entropy compensation and contact position-specific effects with the likely involvement of the peptide surroundings were detected. KinITC analysis revealed a prolonged lifetime of the lectin-glycan complex with increasing glycan valency and with a change in the solvent to D2O.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Tiermedizin > Veterinärwissenschaftliches Department
• Themengebiete: 600 Technik, Medizin, angewandte Wissenschaften > 610 Medizin und Gesundheit
• ISSN: 0006-2960
• Sprache: Englisch