Molecular basis for recognition of the cancer glycobiomarker, LacdiNAc (GalNAc[β1→4]GlcNAc), by Wisteria floribunda agglutinin

From National Research Council Canada

DOIResolve DOI: https://doi.org/10.1074/jbc.M116.750463
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Name affiliation
  1. National Research Council Canada. Human Health Therapeutics
FormatText
TypeArticle
Journal titleJournal of Biological Chemistry
ISSN0021-9258
1083-351X
Volume291
Issue46
Pages24085–24095
Subjectbiomarker; cancer; carbohydrate; carbohydrate-binding protein; lectin; structural biology; x-ray crystallography; agglutinin; glycobiomarker
Abstract
Aberrant glycosylation and the overexpression of specific carbohydrate epitopes is a hallmark of many cancers, and tumor-associated oligosaccharides are actively investigated as targets for immunotherapy and diagnostics. Wisteria floribunda agglutinin (WFA) is a legume lectin that recognizes terminal N-acetylgalactosaminides with high affinity. WFA preferentially binds the disaccharide LacdiNAc (β-d-GalNAc-[1→4]-d-GlcNAc), which is associated with tumor malignancy in leukemia, prostate, pancreatic, ovarian, and liver cancers and has shown promise in cancer glycobiomarker detection. The mechanism of specificity for WFA recognition of LacdiNAc is not fully understood. To address this problem, we have determined affinities and structure of WFA in complex with GalNAc and LacdiNAc. Affinities toward Gal, GalNAc, and LacdiNAc were measured via surface plasmon resonance, yielding KD values of 4.67 × 10-4 m, 9.24 × 10-5 m, and 5.45 × 10-6 m, respectively. Structures of WFA in complex with LacdiNAc and GalNAc have been determined to 1.80-2.32 Å resolution. These high resolution structures revealed a hydrophobic groove complementary to the GalNAc and, to a minor extent, to the back-face of the GlcNAc sugar ring. Remarkably, the contribution of this small hydrophobic surface significantly increases the observed affinity for LacdiNAc over GalNAc. Tandem MS sequencing confirmed the presence of two isolectin forms in commercially available WFA differing only in the identities of two amino acids. Finally, the WFA carbohydrate binding site is similar to a homologous lectin isolated from Vatairea macrocarpa in complex with GalNAc, which, unlike WFA, binds not only αGalNAc but also terminal Ser/Thr O-linked αGalNAc (Tn antigen).
Publication date
PublisherAmerican Society for Biochemistry and Molecular Biology
LanguageEnglish
Peer reviewedYes
NPARC number23002006
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Record modified2017-07-17
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