Roles of the structural units, glycotopes / mammalian N-glycans for Con A-glycan interactions, their codes, and their recognition factors.

The binding property of Con A has been studied intensively and applied widely to glycoconjugates / glycobiology for over 80 years. However, its role and functional relationship of Con A with these mammalian structural units, glycotopes, N-glycan chains, as well as their polyvalent forms in N-glycoproteins involved in the Con A-glycan interactions have not been well defined and organized. In this study, the recognition factors involved in these interactions were analyzed by our well developed method- the enzyme linked lectinosorbent (ELLSA) and inhibition assay.

Recognition factors of Dolichos biflorus agglutinin (DBA) and their accommodation sites.

Dolichos biflorus agglutinin (DBA) is one of the well known plant lectins that are widely used in clinical serology to differentiate human blood group A and A erythrocytes and also applied to glycobiology. However, the knowledge of recognition factors of polyvalent (super) glycotopes in glycans and the roles of functional group and epimer in monosaccharide (sub-monosaccharide recognition factor) have not been well established. The size and shape of the recognition (combining) site of DBA has not been clearly defined.

Loci and motifs of the GalNAcα1 → 3/O related glycotopes in the mammalian glycoconjugates and their lectin recognition roles.

Galα1 → and GalNAcα1 → are the two essential key sugars in human blood group AB active glycotopes, in which GalNAcα1 → related sequences are located at both sides of the nonreducing and the reducing ends of human blood group A active O-glycans. It is also found at the nonreducing ends of GlcNAc N-glycans and glycosphingolipid(GSL) of human blood group A active glycotopes (A) and Forssman antigen (F). When monosaccharides and their α, β anomers are involved in basic units to express the complex size of the combining sites of the GalNAcα1 → specific lectins, they can be divided into a cavity site to accommodate the GalNAcα → key sugar and a subsite with a wide and broad range of recognition area to adopt the rest part of sugar sequences or glycotopes.

Probing sulfatide-tissue lectin recognition with functionalized glycodendrimersomes.

The small 3--sulfated galactose head group of sulfatides, an abundant glycosphingolipid class, poses the (sphinx-like) riddle on involvement of glycan bridging by tissue lectins (sugar code). First, synthesis of head group derivatives for functionalization of amphiphilic dendrimers is performed. Aggregation of resulting (biomimetic) vesicles, alone or in combination with lactose, demonstrates bridging by a tissue lectin (galectin-4).

Glycan structures and their recognition roles in the human blood group ABH/Ii, Le and Sialyl Le active cyst glycoproteins.

Human ovarian cyst glycoproteins (HOC, cyst gps) isolated from pseudomucinous type of human ovarian cyst fluids is one of the richest and pioneer sources for studying biosynthesis, structures and functional roles of blood group ABH, Le, sLe and sLe active glycoproteins. After 70 years of exploration, four top highlights are shared. (i) an updated concept of glycotopes and their internal structures in cyst gps was composited; (ii) the unknown codes of new genes in secreted cyst gps were unlocked as Le and Le; (iii) recognition profiles of cyst glycans and a sialic acid-rich (18%) glycan with lectins and antibodies were shown.

Lectins and ELLSA as powerful tools for glycoconjugate recognition analyses.

Lectins, in combination with our established enzyme-linked lectin sorbent assay (ELLSA) and inhibition study, have been used as powerful tools in many glycoconjugate recognition studies. In this short review, we highlight the following: (i) The recognition profiles of Gal/GalNAc-specific lectins were updated and upgraded. (ii) Based on the cross-specificities of applied lectins, a new classification system was introduced.

Glycan binding profile of a fucolectin-related protein (FRP) encoded by the SP2159 gene of .

The recombinant fucolectin-related protein (FRP) of unknown function, encoded by the SP2159 gene of was expressed in . In this study, its glycan-recognition epitopes and their binding potencies were examined by enzyme-linked lectinosorbent and inhibition assays. The results indicate that FRP reacted strongly with human blood group and l-Fucα1→2-active glycotopes and in their polyvalent (super) forms.

A Large-Area Nanoplasmonic Sensor Fabricated by Rapid Thermal Annealing Treatment for Label-Free and Multi-Point Immunoglobulin Sensing.

Immunoglobulins are important biomarkers to evaluate the immune status or development of infectious diseases. To provide timely clinical treatments, it is important to continuously monitor the level of multiple immunoglobulins. Localized surface plasmon resonance (LSPR)-based nanoplasmonic sensors have been demonstrated for multiplex immunoglobulins detection.

Ocular injury by transient formaldehyde exposure in a rabbit eye model.

Formaldehyde (FA) is frequently used in sterilizing surgical instruments and materials. Exposure to FA is highly concerned for eye tissues. Rabbit corneal epithelial cells were examined for changes after FA exposure.

Increasing the depth of mass spectrometry-based glycomic coverage by additional dimensions of sulfoglycomics and target analysis of permethylated glycans.

Hog or porcine gastric mucin resembles the human source in carrying not only blood group antigens but also the rather rare α4-GlcNAc-capped terminal epitope functionally implicated in protection against Helicobacter pylori infection. Being more readily available and reasonably well characterized, it serves as a good reagent for immunobiological studies, as well as a standard for analytical methodology developments. Current approaches in mass spectrometry (MS)-based glycomic mapping remain vastly inadequate in revealing the full complexity of glycosylation, particularly for cases such as the extremely heterogeneous O-glycosylation of mucosal mucins that can be further sulfated.

Relative intensities of recognition factors at two combining sites of Ralstonia solanacearum lectin (RSL) for accommodating LFucα1-->, DManα1--> and Galβ1-->3/4GlcNAc glycotopes.

Owing to the weak reactivities of monomeric DManα1 and Galβ1-->3/4GlcNAcβ (I(β)/II(β)) glycotopes with Ralstonia solanacearum lectin (RSL), their recognition roles were previously ignored. In this study, the interaction intensities of RSL toward four monomeric glycotopes LFucα1-->, DManα1--> and I(β)/II(β) within two combining sites were established by both enzyme-linked lectinosorbent and inhibition assays. It was found that high density of LFucα1--> complex enhanced the recognition intensities at LFucα1--> site, polyvalent DManα1--> was essential for binding at the DManα1--> site and polyvalent I(β)/II(β) was required at LFucα1--> site.

Human galectin-3 (Mac-2 antigen): defining molecular switches of affinity to natural glycoproteins, structural and dynamic aspects of glycan binding by flexible ligand docking and putative regulatory sequences in the proximal promoter region.

Background: Human galectin-3 (Mac-2 antigen) is a cell-type-specific multifunctional effector owing to selective binding of distinct cell-surface glycoconjugates harboring β-galactosides. The structural basis underlying the apparent preferences for distinct glycoproteins and for expression is so far unknown.

Methods: We strategically combined solid-phase assays on 43 natural glycoproteins with a new statistical approach to fully flexible computational docking and also processed the proximal promoter region in silico.

Recognition roles of the carbohydrate glycotopes of human and bovine lactoferrins in lectin-N-glycan interactions.

Background: Lactoferrin is an iron-binding protein belonging to the transferrin family. In addition to iron homeostasis, lactoferrin is also thought to have anti-microbial, anti-inflammatory, and anticancer activities. Previous studies showed that all lactoferrins are glycosylated in the human body, but the recognition roles of their carbohydrate glycotopes have not been well addressed.

Multiple recognition systems adopting four different glycotopes at the same domain for the Agaricus bisporus agglutinin-glycan interactions.

For the GalNAcalpha1--> specific Agaricus bisporus agglutinin (ABA) from an edible mushroom, the mechanism of polyvalent Galbeta1-->3/4GlcNAcbeta1--> complex in ABA-carbohydrate recognition has not been well defined since Gal and GlcNAc are weak ligands. By enzyme-linked lectinosorbent and inhibition assays, we show that the polyvalent Galbeta1-->3/4GlcNAcbeta1--> in natural glycans also play vital roles in binding and we propose that four different intensities of glycotopes (Galbeta1-3GalNAcalpha1-, GalNAcalpha1-Ser/Thr and Galbeta1-3/4GlcNAcbeta1-) construct three recognition systems at the same domain. This peculiar concept provides the most comprehensive mechanism for the attachment of ABA to target glycans and malignant cells at the molecular level.

Duality of the carbohydrate-recognition system of Pseudomonas aeruginosa-II lectin (PA-IIL).

The study of Pseudomonas aeruginosa-II lectin (PA-IIL) complexes with Man derivatives as a recognition factor has been neglected since its monomer is a very weak ligand. Here, the roles of Man oligomers and complexes in PA-IIL carbohydrate-recognition were studied by both enzyme-linked lectinosorbent and inhibition assays. From the results obtained, it is proposed that high density weak -OH conformation as seen in yeast mannan is also an important PA-IIL recognition factor.

Recognition intensities of submolecular structures, mammalian glyco-structural units, ligand cluster and polyvalency in abrin-a-carbohydrate interactions.

Abrin-a is the most toxic fraction of lectins isolated from Abrus precatorius seeds and belongs to the family of type 2 ribosome inactivating proteins (RIP). This toxin may act as a defense molecule in plants against viruses, fungi and insects, where attachment of abrin-a to the exposed glycans on the surface of target cells is the crucial and initial step of its cytotoxicity. Although it has been studied for over four decades, the recognition factors involved in abrin-a-carbohydrate interaction remains to be clarified.

Roles of mammalian structural units, ligand cluster and polyvalency in the Abrus precatorius agglutinin and glycoprotein recognition process.

Previous studies on one of the toxic type 2 ribosome inactivating proteins (RIP), Abrus precatorius agglutinin (APA), have shown that the recognition domains of APA are restricted to monomers of Galbeta1-3GalNAc (T, Thomsen-Friedenreich glycotope) and Galbeta1-3/4GlcNAc (blood group precursor type I/II sequences); which are essential but play a minor role in the recognition process. In this study, APA recognition factors were expanded to include ligand clusters and polyvalent glycotopes by enzyme-linked lectinosorbent binding and inhibition assays. Based on the results of molar relative potency, the essential mammalian structural units are Galbeta1-3GalNAcalpha/beta1- (T(alpha)/T(beta))>Galalpha1-4Gal (E)>Galbeta1-3/4GlcNAc (I/II) and avidity for tri-/di-antennary II(beta), T, E and II monomers was found to be 7.

Identification of blood group A/A-Leb/y and B/B-Leb/y active glycotopes co-expressed on the O-glycans isolated from two distinct human ovarian cyst fluids.

Although the individual human blood group A and B determinants are well defined, their co-expression pattern on a particular glycan carrier in individuals of blood group AB status has not been delineated. To address this issue, complex O-glycans were isolated from two distinct sources of human ovarian cyst glycoproteins (HOC 89 and Cyst 19) and profiled by advanced MS analyses, in conjunction with defining their binding characteristics against a panel of lectins and monoclonal antibodies. The major O-glycans of HOC 89 were found to correspond to sialyl Tn, mono- and di-sialyl T structures, whereas those of Cyst 19 were apparently more heterogeneous and extended to larger sizes.

Multivalent human blood group ABH and Lewis glycotopes are key recognition factors for a LFuc>Man binding lectin from phytopathogenic Ralstonia solanacearum.

Ralstonia solanacearum lectin (RSL), that might be involved in phytopathogenicity, has been defined as LFuc>>Man specific. However, the effects of polyvalency of glycotopes and mammalian structural units on binding have not been established. In this study, recognition factors of RSL were comprehensively examined with natural multivalent glycotopes and monomeric ligands using enzyme linked lectin-sorbent and inhibition assays.