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Beckwith DM, FitzGerald FG, Rodriguez Benavente MC, Mercer ER, Ludwig AK, Michalak M, Kaltner H, Kopitz J, Gabius HJ, Cudic M. Calorimetric Analysis of the Interplay between Synthetic Tn Antigen-Presenting MUC1 Glycopeptides and Human Macrophage Galactose-Type Lectin. Biochemistry 2021; 60:547-558. [PMID: 33560106 PMCID: PMC8269692 DOI: 10.1021/acs.biochem.0c00942] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 01/31/2021] [Indexed: 12/25/2022]
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 α-linked to serine/threonine residues (Tn antigen, CD175) and its α2,6-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 μM for monoglycosylated peptides to 0.6 μM 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.
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Affiliation(s)
- Donella M. Beckwith
- Department of Chemistry and Biochemistry, Charles E.
Schmidt College of Science, Florida Atlantic University, Boca
Raton, Florida 33431, United States
| | - Forrest G. FitzGerald
- Department of Chemistry and Biochemistry, Charles E.
Schmidt College of Science, Florida Atlantic University, Boca
Raton, Florida 33431, United States
| | - Maria C. Rodriguez Benavente
- Department of Chemistry and Biochemistry, Charles E.
Schmidt College of Science, Florida Atlantic University, Boca
Raton, Florida 33431, United States
| | - Elizabeth R. Mercer
- Department of Chemistry and Biochemistry, Charles E.
Schmidt College of Science, Florida Atlantic University, Boca
Raton, Florida 33431, United States
| | - Anna-Kristin Ludwig
- Ludwig-Maximilians-University
Munich, Institute of Physiological Chemistry, Faculty of Veterinary
Medicine, Veterinärstrasse 13, 80539 Munich, Germany
| | - Malwina Michalak
- Department of Applied Tumor Biology, Institute of
Pathology, Medical School of the Ruprecht-Karls-University
Heidelberg, Im Neuenheimer Feld 224, 69120 Heidelberg,
Germany
| | - Herbert Kaltner
- Ludwig-Maximilians-University
Munich, Institute of Physiological Chemistry, Faculty of Veterinary
Medicine, Veterinärstrasse 13, 80539 Munich, Germany
| | - Jürgen Kopitz
- Department of Applied Tumor Biology, Institute of
Pathology, Medical School of the Ruprecht-Karls-University
Heidelberg, Im Neuenheimer Feld 224, 69120 Heidelberg,
Germany
| | - Hans-Joachim Gabius
- Ludwig-Maximilians-University
Munich, Institute of Physiological Chemistry, Faculty of Veterinary
Medicine, Veterinärstrasse 13, 80539 Munich, Germany
| | - Maré Cudic
- Department of Chemistry and Biochemistry, Charles E.
Schmidt College of Science, Florida Atlantic University, Boca
Raton, Florida 33431, United States
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