Lectins Concanavalin

AMPA receptors desensitize within milliseconds upon exposure to AMPA, and kainate receptors likewise upon exposure to kainate. AMPA and kainate receptors can be securely distinguished from one another by their response to two drugs, cyclothiazide and the lectin concanavalin A [10], Cyclothiazide relieves AMPA receptor desensitization without affecting kainate receptors. 

A fluorescent tag (fluorescein isothiocyanate) attached to the lectin Concanavalin A is useful in staining yeast cell wall fragments (Siebert et al., 1981). Concanavalin A specifically binds to mannan, which is prominent in yeast cell walls. 

An ultraviolet (UV) monitor is most commonly used in CE experiment. Such interaction studies using the ACE method can also be hampered by the inadequate sensitivity of UV detection. Fluorescence labeling and laser-induced fluorescence (LIF) detection have been employed to enhance the sensitivity of this method, as shown by the mobility-shift assay of fluorescence-labeled sugar caused by the interaction with the lectin, concanavalin A (74). When fluorescent dyes are employed for labeling, LIF detection provides several hundred times more sensitivity than UV detection. 

If the lectin Concanavalin A shall be used, dilute it in Soln. B. Incubate as described above. After washing, incubate with 50 pg/ml HRP in Soln. B for 30 min, wash with Soln. B again, and stain as described in Protocols 2.5.4.1 or 2.5.5.I. 

To immobilize a protein the biologic activity of which depends on a cofactor, this cofactor has to be present in sufficient concentration during the immobilization step. Thus, for example, the lectin Concanavalin A is immobilized in the presence of a buffer containing 0.1 M glucose or a-methylmannoside, 1 mM calcium chloride and 1 mM manganese chloride. 

Christensen et al. [93] successfully obtained a divalent cluster having -600-1500 enhanced binding properties. We have also demonstrated that dendritic mannosides such as 66 (Scheme 11) can provide up to 100-fold higher affinity (on a per-mannoside basis) when used to inhibit the binding of plant lectins (Concanavalin A and pea lectins) to yeast mannan [85]. As these interactions are at the origin of host infections by fimbriated bacteria, mannoside dendrimers can form the basis of novel antiadhesin molecules. 

This fraction contained carbohydrates typical of membrane glycoproteins and was especially rich in galactose and sialic acid. Glycoproteins in this fraction avidly bound the lectin Concanavalin A. 

Fig. 46. Effect of addition of lectin Concanavalin A and a-methyl-man-nopyranoside to vesicles of (48), measured by change of absorption at 360 nm...

Western blotting has become an important, modern technique for analysis and characterization of proteins. The procedure consists of, first, the electrophoretic transfer (blotting) of proteins from polyacrylamide gels to synthetic membranes. The transferred blots are then probed using immunological detection methods to identify proteins of specific structure and/or function. In this experiment, bovine serum will be fractionated by SDS-PAGE and the proteins blotted onto a nitrocellulose membrane. Serum glycoproteins will be identified by their specific interaction with the lectin concanavalin A. 

The gel containing lectin, concanavalin A, was also found to undergo distinct swelling behavior in response to different saccharides (ionic and non-ionic saccharides) [24]. 

Blood Groups XLIII. The Interaction of Blood Group Substances from Various Sources with a Plant Lectin, Concanavalin A, J. Immunol. (1969) 102,1354. 

After Zemplen treatment under usual conditions, the sparingly water-soluble hexamers 49 and 51 were obtained in quantitative yields. Their modest solubility in water has however not jeopardized their biological evaluations in solid-phase competitive inhibition assays as well as in their cross-linking abilities with a model plant lectin, Concanavalin A, known to form cross-linked lattices in the presence of multiantennary glycans (39). 

It is only within the past decade that lectins have been purified to a homogeneity demonstrable by physicochemical and immunological criteria. Although Sumner and Howell crystallized the jack-bean lectin (concanavalin A or con A) over forty years ago, they were unable to free it completely from carbohydrate contaminants.102... 

The binding of horseradish peroxidase (HRP) to the lectin Concanavalin A (101) serves as a model. The glycosylated enzyme is utilized as an enzyme-... 

The plant lectin concanavalin A, a metalloprotein isolated from the jack bean, has also received considerable attention. (588-590,630,631) Using the stopped flow NMR technique three distinct conformation states of the protein, when it is bound to Mn, Ca, and a-methyl-D-mannoside, (630) have been deduced. 

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