Disease relevance of N-acetyllactosamine

• Thus, these data imply that capping N-acetyllactosamine with alphaGal or alphaFuc and the corresponding reduction in sialylation of BL6-2 melanoma cells were associated with reduction of their metastatic potential [1].
• Haemophilus ducreyi, the cause of the sexually transmitted disease chancroid produces a lipooligosaccharide (LOS) containing a terminal sialyl N-acetyllactosamine trisaccharide [2].
• Neisseria gonorrhoeae that infect men have lipooligosaccharides with terminal N-acetyllactosamine repeats [3].
• Several N-acetyllactosamine (LacNAc) derivatives were tested as acceptors for alpha 1,3-L-fucosyltransferase present in human ovarian cancer sera and ovarian tumor [4].
• Our biochemical studies conclusively demonstrate that lupus IgG V(H)4.34 Abs target a developmentally regulated B220-specific glycoform of CD45, and more specifically, an N-linked N-acetyllactosamine determinant preferentially expressed on naive B cells that is sterically masked by sialic acid on B220-positive memory B cells [5].

High impact information on N-acetyllactosamine

• Both antibodies bound to a series of neutral glycosphingolipids from human erythrocytes and neutrophils that have a type 2 (Gal beta 1----4GlcNAc) or N-acetyllactosamine structure [6].
• The activity of 3F11 with human adult and infant treated and untreated erythrocytes with N-acetyllactosamine glycosphingolipids, and with LOS was very similar, if not identical, in specificity to 1B2, an mAb prepared from mice inoculated with a linear N-acetyllactosamine glycosphingolipid [6].
• Antibody binding also was blocked by the presence of fucose linked to the penultimate glucosamine residue of N-acetyllactosamine glycosphingolipids [6].
• The high resolution X-ray crystallographic analyses of three crystal forms of bovine galectin-1 in complex with biantennary saccharides of N-acetyllactosamine type reveal infinite chains of lectin dimers cross-linked through N-acetyllactosamine units located at the end of the oligosaccharide antenna [7].
• The crystal structure of a 14-kDa bovine spleen S-lectin complexed with the disaccharide N-acetyllactosamine at 1.9-A resolution reveals a surprising structural relationship to legume lectins, despite the lack of sequence homology [8].

Chemical compound and disease context of N-acetyllactosamine

• Embryonal carcinoma (EC) cells possess a complex cell surface glycoconjugate called lactosaminoglycan, whose core structure is composed of repeating N-acetyllactosamine (Gal leads to GlcNAc) disaccharides [9].
• In functional assays alpha 2,3-ST and alpha 1,3- or 1,4-FT activities were observed in adenocarcinoma cell lysates to exogenous N-acetyllactosamine and lacto-N-biose acceptors and to their sialylated derivatives, leading to the synthesis of the sialyl-N-acetyllactosamine and s(Lex) or the sialyllacto-N-biose and s(Lea), respectively [10].
• Glucosylated N-acetyllactosamine O-antigen chain in the lipopolysaccharide from Helicobacter pylori strain UA861 [11].
• The major lipooligosaccharides of the sexually transmitted pathogen Haemophilus ducreyi 35000 have been previously found to terminate in N-acetyllactosamine and sialyl-N-acetyllactosamine, Neu5Ac alpha 2-->3Gal beta 1-->4GlcNAc (W. Melaugh, N. J. Phillips, A. A. Campagnari, M. V. Tullius, and B. W. Gibson, Biochemistry 33: 13070-13078, 1994) [12].

Biological context of N-acetyllactosamine

• The conversion of oligomannose to N-acetyllactosamine (complex) oligosaccharides is hindered to different extents at the four glycosylation sites, so that the complex/oligomannose ratio decreases in the order E1-Asn139 greater than E2-Asn196 greater than E1-Asn245 greater than E2-Asn318 [13].
• On the other hand, N-acetyllactosamine (Gal beta 1-->4GlcNAc) and its analogs were the strongest inhibitors toward HOL-II-induced hemagglutination [14].
• When expressed by transfection in cultured cell lines, this gene determines expression of a fucosyltransferase capable of efficiently utilizing N-acetyllactosamine to form the Lewis x determinant (Gal beta 1----4[Fuc alpha 1----3]GlcNAc) [15].
• At the nonreducing termini, Le(b)/Le(a) or tandem repeats of the Le(a) structure prevail, a substantial proportion of which are attached via internal Le(x) or N-acetyllactosamine units to the trimannosyl core [16].
• Although the glycoconjugate composition of human gastric epithelial cells is not known in detail it is proposed that repeating N-acetyllactosamine units of glycoconjugates may serve as bacterial attachment sites in the stomach [17].

Anatomical context of N-acetyllactosamine

• Reduction in cell membrane sialylation in the alpha 1,3GT gene-transfected melanoma cells is probably due to the competition between alpha 1,3GT with alpha 2,3 sialyltransferase or alha 2,6 sialyltransferase for the common acceptor N-acetyllactosamine in the Golgi apparatus [18].
• Branch specificity of bovine colostrum CMP-sialic acid: Gal beta 1----4GlcNAc-R alpha 2----6-sialyltransferase. Sialylation of bi-, tri-, and tetraantennary oligosaccharides and glycopeptides of the N-acetyllactosamine type [19].
• The distribution of the repeating N-acetyllactosamine unit was also examined in a cell line ( PHAR 2.1) that is deficient in UDP-GlcNAc:alpha-mannoside beta 1,6-N-acetylglucosaminyltransferase [20].
• In addition the enzyme together with calf thymus UDP-Gal:GlcNAc beta-R beta 1----4-galactosyltransferase was capable of catalyzing the synthesis of a series of oligomers of N-acetyllactosamine [21].
• Northern blot analysis demonstrated that transcripts for Gal3ST-3 are predominantly expressed in the brain, kidney, and thyroid where the presence of 3'-sulfation of N-acetyllactosamine has been reported [22].

Associations of N-acetyllactosamine with other chemical compounds

• Mitogenic leukoagglutinin from Phaseolus vulgaris binds to a pentasaccharide unit in N-acetyllactosamine-type glycoprotein glycans [23].
• The precursor structures were: type 2 chain H-antigen, Fuc alpha 1 leads to 2 Gal beta 1 leads to 4 GlcNAc-R (A and B precursor); and N-acetyllactosamine, Gal beta 1-4GlcNAc-R (H-precursor), in which Fuc is L-fucose, Gal is galactose, and GIcNAc is N-acetyl-D-glucosamine [24].
• We report here the x-ray crystal structure of the human galectin-3 CRD, in complex with lactose and N-acetyllactosamine, at 2.1-A resolution [25].
• Although the galaptin did not appear to recognize N-acetylglucosamine as a monosaccharide, the presence of this sugar penultimate to galactose increased the binding affinity by as much as 500-fold, as was the case for N-acetyllactosamine [26].
• The mass spectrometry results indicated that the predominant glycoforms at the three glycosylation sites of these beta-subunits were a combination of the tetraantennary glycan form and the unusual glycan form of tetraantennary with a limited number of repeating N-acetyllactosamine units [27].

Gene context of N-acetyllactosamine

• Removal of polylactosamine chains by endo-beta D-galactosidase digestion significantly reduced the electrophoretic mobility of the immunoreactive bands, suggesting that HLA-G, unlike class Ib molecules studied to date, carries N-acetyllactosamine units [28].
• The HNK-1 glycan synthesis is initiated by the addition of beta1,3-linked GlcA to N-acetyllactosamine followed by sulfation of the C-3 position of GlcA [29].
• The amounts of T antigen and N-acetyllactosamine oligosaccharides on MUC5B increased during the first half of the cycle, peaked at midcycle, and dramatically dropped at the end of the cycle [30].
• Like mammalian prototype galectin-1, Drgal1-L2 preferentially binds to N-acetyllactosamine [31].
• In addition, AQN-3 binds preferentially to glycoproteins with either a linear or tri- and tetraantennary carbohydrates than to those containing diantennary N-acetyllactosamine structures [32].

Analytical, diagnostic and therapeutic context of N-acetyllactosamine

• Erythropoietin also contains N-glycans with a few N-acetyllactosamine repeats, which can be enriched by tomato lectin affinity chromatography [33].
• Results from enzyme-linked immunosorbent assays show that an N-acetyllactosamine repeating sequence is not required; however, the N-acetyllactosamine repeating sequence does appear to enhance the binding of MAL to a series of glycolipids [34].
• Molecular cloning and expression of a novel human beta-Gal-3-O-sulfotransferase that acts preferentially on N-acetyllactosamine in N- and O-glycans [22].
• A practically complete removal of terminal alpha-Gal residues (as evaluated by flow cytometry with Bandeiraea simplicifolia isolectin B4) and concomitant exposure of N-acetyllactosamine were obtained without altering cell viability [35].
• These results suggest that increase of sialylated tetraantennary complex-type sugar chains without N-acetyllactosamine repeating units of B16 melanoma cells might correlate with the higher lung-colonizing ability after intravenous injection [36].

References