Novel Fluorescent Glycan Microarray Strategy Reveals Ligands for Galectins

• Authors: Xuezheng Song, Emory University; Baoyun Xia, Emory University; Sean R. Stowell, Emory University; Yi Lasanajak, Emory University; David Smith, Emory University; Richard Cummings, Emory University
• Journal Title: Cell Chemistry Biology
• Volume: Volume 16, Number 1
• Publisher: Elsevier (Cell Press): 12 month embargo | 2009-01-30, Pages 36-47
• Type of Work: Article | Post-print: After Peer Review
• Publisher DOI: http://doi.org/10.1016/j.chembiol.2008.11.004
• Subjects: Health Sciences, General; Chemistry, Biochemistry
• Keywords: galectin; glycan microarray; fluorescent labeling; immobilization; functional glycomics

Abstract

Summary Galectin-1 (Gal-1) and galectin-3 (Gal-3) are widely expressed galectins with immunoregulatory functions in animals. To explore their glycan specificity, we developed microarrays of naturally occurring glycans using a novel bifunctional fluorescent linker, 2-amino-N-(2-aminoethyl)-benzamide (AEAB), directly conjugated through its arylamine group by reductive amination to free glycans to form glycan-AEABs (GAEABs). Glycans from natural sources were used to prepare over 200 GAEABs, which were purified by multidimensional HPLC and covalently immobilized onto NHS-activated glass slides via their free alkylamine. Fluorescence-based screening demonstrated that Gal-1 recognizes a wide variety of complex N-glycans, whereas Gal-3 primarily recognizes poly-N-acetyllactosamine-containing glycans independent of N-glycan presentation. GAEABs provide a general solution to glycan microarray preparation from natural sources for defining the specificity of glycan-binding proteins.