Novel Fluorescent Glycan Microarray Strategy Reveals Ligands for Galectins

• Type of Material: Article
• 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
• Language: English
• Date: 2009-01-30
• Publisher: Elsevier (Cell Press): 12 month embargo
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2009, Elsevier
• License: Creative Commons Attribution-NonCommerical-NoDerivs 3.0 Unported
• Final Published Version (URL): http://dx.doi.org/10.1016/j.chembiol.2008.11.004
• Title of Journal or Parent Work: Cell Chemistry Biology
• ISSN: 1074-5521
• Volume: 16
• Issue: 1
• Start Page: 36
• End Page: 47
• Grant/Funding Information: This work was supported by in part by an NIH Bridge Grant to R.D.C from the Consortium for Functional Glycomics (GM62116) and NIH grant GM085448 to D.F.S.
• Keywords: galectin; glycan microarray; immobilization; functional glycomics; fluorescent labeling
• Research Categories: Chemistry, Biochemistry; Health Sciences, General

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.