Lectins and Neoglycoproteins in Histopathology

180

Protein-carbohydrate interaction is exploited in cell adhesion mechanisms besides the recognition of peptide motifs. The sugar code thus significantly contributes to the intriguing specificity of cellular selection of binding partners. Focusing on two classes of lectins (selectins and galectins), it is evident that their functionality for mediation of adhesive contacts is becoming increasingly appreciated, as is the integration of this type of interaction with other recognition modes to yield the noted specificity. The initial contact formation between leukocytes and activated endothelium makes use of selectins to guide lymphocyte trafficking. In addition to the three selectins which bind a distinct array of ligands, galectin-1 and galectin-3 and possibly other members of this family are involved in cell-cell or cell-matrix interactions. This review summarizes structural and functional aspects of these two classes of endogenous lectins relevant for cell adhesion. oooooooooooooooooooo

Section: Galectinsmentioning

confidence: 99%

Animal Lectins as Cell Adhesion Molecules

Kaltner¹,

Stierstorfer²

1998

180

“…Especially the results of lectin studies should be interpreted with care, since (1) lectins with identical sugar specificities may bind differently in the same tissue, and (2) the binding pattern of a certain lectin may vary with the tissue fixation and processing protocol used [Walker, 1989;Danguy and Gabius, 1993;Gabius, 1997;Kannan and Nair, 1997;Danguy et al, 1998]. Therefore, cryosections may be the preferred material for certain lectin-histochemical studies.…”

Section: Localization Of Glycoconjugatesmentioning

confidence: 99%

Strategies for Glycoconjugate Analysis

Geyer

1998

Glycoconjugates such as glycoproteins and glycosphingolipids exhibit multiple functions in biological systems. A correlation of functional features with defined structural parameters, however, presupposes detailed information on the glycoconjugates’ carbohydrate moieties including the type of linkage of the oligosaccharide chain(s), monosaccharide composition as well as sequence, linkage positions and anomeric configurations of individual sugar monomers. Chemical and biochemical analyses are often impeded by the limited amounts of sample available and the vast structural heterogeneity of glycoconjugate glycans, thus requiring highly sensitive and efficient methods for detection, separation and structural elucidation of these carbohydrates. The aim of the article is to present suitable strategies for structural characterization of glycoconjugate glycans and to briefly review some of the techniques commonly used in this field.

“…Localization in tissue sections, e.g. to detect developmental or malignancy-associated changes in glycoconjugate display, similarly takes advantage of this panel of probes [Mann, 1988;Bourillon and Aubery, 1989;Hakomori, 1989Hakomori, , 1998Varki and Marth, 1995;Kannan and Nair, 1997;Brinck et al, 1998;Brockhausen et al, 1998;Mann and Waterman, 1998;Zschäbitz, 1998]. Its proven versatility not only fuels work on elucidation of the functions of these proteins in plants and invertebrates such as the horseshoe crab [Etzler, 1985;Vasta, 1992;Peumans and van Damme, 1995;Gabius, 1997a;Rüdiger, 1997Rüdiger, , 1998].…”

Section: Introductionmentioning

confidence: 99%

Lectin Ligands: New Insights into Their Conformations and Their Dynamic Behavior and the Discovery of Conformer Selection by Lectins

Lieth

Siebert

Kožár³

et al. 1998

The mysteries of the functions of complex glycoconjugates have enthralled scientists over decades. Theoretical considerations have ascribed an enormous capacity to store information to oligosaccharides. In the interplay with lectins sugar-code words of complex carbohydrate structures can be deciphered. To capitalize on knowledge about this type of molecular recognition for rational marker/drug design, the intimate details of the recognition process must be delineated. To this aim the required approach is garnered from several fields, profiting from advances primarily in X-ray crystallography, nuclear magnetic resonance spectroscopy and computational calculations encompassing molecular mechanics, molecular dynamics and homology modeling. Collectively considered, the results force us to jettison the preconception of a rigid ligand structure. On the contrary, a carbohydrate ligand may move rather freely between two or even more low-energy positions, affording the basis for conformer selection by a lectin. By an exemplary illustration of the interdisciplinary approach including up-to-date refinements in carbohydrate modeling it is underscored why this combination is considered to show promise of fostering innovative strategies in rational marker/drug design.