Determination lectins

The final chapter is dedicated to the state-of-the-art methods for determining lectin affinity and specificity for oligosaccharides. These play a key role in many biological processes relevant to cell communication and disease states, and are involved in cancer development and metastasis, inflammation and host-pathogen recognition. 

To study the binding mode of the yS-D-galactopyranosyl residue of the Lewis b human blood-group determinant to its monoclonal antibody or to a lectin, methyl 2-acetamido-2-deoxy-3-0-(6-deoxy-6-fluoro-2-0-a-L-fuco-pyranosyl-y -D-galactopyranosyl)-4-0-a-L-fucopyranosyl-/ -D-glucopyrano-side was synthesized. ... 

F. B. Dazzo and D. H. Hubbell, Gro.ss-reactive antigens and lectin as determinants of symbiotic specificity in the Rhizobiiim-c o er association. Appl. Microbiol. 30 1017-1033 (1975). 

TES-32 is the most abundant single protein product secreted by the parasite. It is also heavily labelled by surface iodination of live larvae (Maizels et al., 1984, 1987), and is known by monoclonal antibody reactivity to be expressed in the cuticular matrix of the larval parasite (Page et al, 1992a). TES-32 was cloned by matching peptide sequence derived from gel-purified protein to an expressed sequence tag (EST) dataset of randomly selected clones from a larval cDNA library (Loukas et al., 1999). Because of the high level of expression of TES-32 mRNA, clones encoding this protein were repeatedly sequenced and deposited in the dataset (Tetteh et al., 1999). Full sequence determination showed a major domain with similarity to mammalian C-type (calcium-dependent) lectins (C-TLs), together with shorter N-terminal tracts rich in cysteine and threonine residues. Native TES-32 was then shown to bind to immobilized monosaccharides in a calcium-dependent manner (Loukas et al., 1999). 

Several other C-type lectins have since been found in Toxocara (Fig. 12.4). Two are simple variants of TES-32, differing by 13-17% in amino acid sequence but with identical ligand binding sites these have been termed CTL-2 and CTL-3. It has yet to be determined whether these additional lectins are alleles or represent different coding loci, and it has not been established whether they are also secreted. A fourth lectin, CTL-4, corresponds to TES-70 (Loukas et al, 2000), as described below. In addition, there is some evidence that TES-45 and TES-55 are lectins, as detailed below. 

Thalhammer, A., Everts, I., and Hollmann, M. (2002) Inhibition by lectins of glutamate receptor desensitization is determined by the lectin s sugar specificity at kainate but not AMPA receptors. Mol. Cell. Neurosci. 21, 521-33. 

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