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Carbohydrate Specificity of Chicken and Human Tandem-Repeat-Type Galectins-8 in Composition of Cells

O. A. Vokhmyanina1, E. M. Rapoport1, I. M. Ryzhov1, E. Yu. Korchagina1, G. V. Pazynina1, V. V. Severov1, H. Kaltner2, S. André2, H.-J. Gabius2, and N. V. Bovin1*

1Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, ul. Miklukho-Maklaya 16/10, 117997 Moscow, Russia; fax: (495) 330-5592; E-mail: bovin@carb.ibch.ru

2Institute of Physiological Chemistry, Faculty of Veterinary Medicine, Ludwig-Maximilians-University, Veterinärstr. 13, D-80539 Munich, Germany; E-mail: gabius@tiph.vetmed.uni-muenchen.de

* To whom correspondence should be addressed.

Received April 27, 2011
The network of adhesion/growth-regulatory galectins in chicken (chicken galectin, CG) has only one tandem-repeat-type protein, CG8. Using a cell-based assay and probing galectin reactivity with a panel of fluorescent neoglycoconjugates (glycoprobes), its glycan-binding profile was determined. For internal validation, human galectin-8 (HG8) was tested. In comparison to HG8, CG8 showed a rather similar specificity: both galectins displayed high affinity to blood group ABH antigens as well as to 3′-sialylated and 3′-sulfated lactosamine chains. The most remarkable difference was found to be an ability of HG8 (but not CG8) to bind the disaccharide Galβ1-3GlcNAc (Lec) as well as branched and linear oligolactosamines. The glycan-binding profile was shown to be influenced by glycocalix of the cell, where the galectin is anchored. Particularly, glycosidase treatment of galectin-loaded cells led to the change of the profile. Thus, we suppose the involvement of cis-glycans in the interaction of cell-anchored galectins with external glycoconjugates.
KEY WORDS: ABH blood group antigens, galectin, cell glycoconjugates

DOI: 10.1134/S0006297911100130