Chemical Modification of Lectins by Group-Specific Reagents
Modification of certain groups of amino acid side chains serves two experimental purposes. It makes it possible to infer which groups can be target for labeling reagents without adversely affecting the ligand-binding properties. When modification is carried out in the absence or presence of a suitable ligand, any differential effect hints at the involvement of certain groups in ligand binding. Impairment of ligand binding only in the absence of the ligand is suggestive evidence for a spatial association of the respective type of side chain to the binding site. Access to such groups should be blocked by the specific glycomolecule. A selection of common reactions to achieve selective side chain modification is given from the possible panel (Glazer et al. 1976). It is necessary to run control reactions for each individual type of modification in the absence of reagents under identical conditions to reliably assess the impact of actual modification on the lectin’s binding capacity. The experimental part illustrates the conditions used for a fetuin-binding protein, calcyclin.
KeywordsBorate Buffer Arginine Residue Amino Acid Side Chain Sodium Borate Suitable Ligand
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