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1.
The gastrulating chick embryo expresses two galactoside-binding lectins of 14 kDa and 16 kDa. These lectins are present in the area pellucida and area opaca, and in the latter are concentrated in the endoderm. Since the area opaca is the progenitor of the yolk sac, we studied the galactose-binding lectins during the development of this extraembryonic organ. In the yolk sac, lectin expression surges between 2 and 4 days, and thereafter remains constant throughout development. Using monoclonal antibodies (mAbs) specific to the 16 kDa yolk sac lectin, and a panel of polyclonal antibodies to the 14 kDa and 16 kDa lectins we studied lectin expression. The mAbs inhibit the hermagglutinating activity of extracts from chick yolk sac, embryonic pectoral muscle, and adult liver, but have no effect on the hemagglutinating activity of extracts from the adult intestine. Immunolocalization studies with the mAbs and polyclonal antibodies indicate that in the less differentiated endodermal cells of the area vitellina the 16 kDa lectin is present in discrete lectin-rich inclusions. In contrast, within the maturing endodermal epithelium of area vasculosa the 16 kDa lectin is present around the intracellular yolk platelets, and is associated with the cytoplasmic matrix. The 16 kDa lectin is also found at the apical cell surface of the yolk sac epithelium, in some regions closely associated with the plasma membrane. The 14 kDa lectin is distributed intracellularly surrounding the yolk platelets of the maturing yolk sac endoderm. The surge in expression of the 16 kDa lectin at the time of expansion of the area opaca suggests that it may be involved in the spreading of this area. Our findings also indicate that as the yolk sac endoderm differentiates into an epithelium intracellular lectin expression changes from predominantly organelle associated to cytoplasm associated. The association of both lectins with yolk suggest that the lectins may also be involved in the processing of intracellular and extracellular yolk proteins. These results, in con junction with previous findings indicating the presence of these lectins in the extracellular matrix (Didier et al., Histochemistry 100:485, 1993; Zalik et al., Intl J Dev Biol 38:55–68, 1994) indicate that these lectins play multiple roles in embryonic development. 相似文献
2.
Oguri S 《Glycoconjugate journal》2005,22(7-9):453-461
The sugar chain-binding specificity of tomato lectin (LEA) against glycoproteins was investigated qualitatively using lectin
blot analysis. Glycoproteins containing tri- and tetra-antennary complex-type N-glycans were stained with LEA. Unexpectedly,
glycoproteins containing high mannose-type N-glycans and a horseradish peroxidase were stained with LEA. LEA blot analysis
of the glycoproteins accompanied by treatment with exoglycosidase revealed that the binding site of LEA for the complex-type
N-glycans was the N-acetyllactosaminyl side chains, whereas the proximal chitobiose core appeared to be the binding site of LEA for high mannose-type
N-glycans. Despite these results, the glycoproteins did not inhibit the hemagglutinating activity of LEA. Among the chitin-binding
lectins compared, potato tuber lectin showed specificity similar to LEA on lectin blot analysis, while Datura stramonium lectin and wheat germ agglutinin (WGA) did not interact with glycoproteins containing high mannose-type N-glycans, except
that RNase B was stained by WGA.
Based on these observations, LEA blot analysis was applied to sugar chain analysis of tomato glycoproteins. The most abundant
LEA-reactive glycoprotein was purified from the exocarp of ripe tomato fruits, and was identified as the tomato anionic peroxidase1
(TAP1). These results suggest that LEA interacts with glycoproteins produced by tomatoes, which participate in biological
activities in tomato plants. 相似文献
3.
Fumio Yagi Mariko Miyamoto Tamami Abe Yuji Minami Kenjiro Tadera Irwin J Goldstein 《Glycoconjugate journal》1997,14(2):281-288
A lectin was isolated from fruiting bodies of Agrocybe cylindracea by two ion-exchange chromatographies and gel filtration on Toyopearl HW55F. The lectin was homogeneous on polyacrylamide
gel electrophoresis and its molecular mass was determined to be 30 000 by gel filtration, and 15 000 by sodium dodecylsulfate
polyacrylamide gel electrophoresis, signifying a dimeric protein.
Its carbohydrate-binding specificity was investigated both by sugar-hapten inhibition of hemagglutination and by enzyme-linked
immunosorbent assay. The inhibition tests showed the affinity of the lectin to be weakly directed toward sialic acid and lactose,
and the enhanced affinity toward trisaccharides containing the NeuAcα2,3Galβ-structure. Importantly, the lectin strongly interacted with glycoconjugates containing NeuAcα2,3Galβ1,3GlcNAc-/GalNAc sequences.
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
4.
Paliakkara L. Jaison Vadakkedath M. Kannan Mandagini Geetha Padinjaradath S. Appukuttan 《Journal of biosciences》1993,18(2):187-193
Naturally occurring serum IgG against terminal α-galactoside epitopes (anti-Gal), present exclusively in man, apes and old
world monkeys, was used as probe for these epitopes in human brain. Human brain grey matter soluble glycoproteins enriched
inα galactosyl groups by affinity chromatography on jacalin-sepharose, specifically binds to human anti-Gal in immuno dot
blots. Anti-Gal recognized exclusively the terminal α galactoside epitope in human brain glycoproteins since binding was abolished
by the presence of 1-0-methyl α-D-galactopyranoside as well as by pretreatment of glycoproteins with coffee bean α-galactosidase.
Anti-Gal-peroxidase staining of jacalin-binding human brain glycoproteins in western immuno blots revealed mainly five anti-Gal-binding
polypeptides withM
r
(in kDa) of 94, 108, 180, 210 and 230 respectively. Since the presence of anti-Gal in higher animals accompanies suppression
of the corresponding epitope in most tissues, apparently to maintain immunological balance, possible implications of the above
observation for autoimmunity, tumor metastasis and infection are discussed. 相似文献
5.
The crystal structure of a complex of methyl-alpha-D-mannoside with banana lectin from Musa paradisiaca reveals two primary binding sites in the lectin, unlike in other lectins with beta-prism I fold which essentially consists of three Greek key motifs. It has been suggested that the fold evolved through successive gene duplication and fusion of an ancestral Greek key motif. In other lectins, all from dicots, the primary binding site exists on one of the three motifs in the three-fold symmetric molecule. Banana is a monocot, and the three motifs have not diverged enough to obliterate sequence similarity among them. Two Greek key motifs in it carry one primary binding site each. A common secondary binding site exists on the third Greek key. Modelling shows that both the primary sites can support 1-2, 1-3, and 1-6 linked mannosides with the second residue interacting in each case primarily with the secondary binding site. Modelling also readily leads to a bound branched mannopentose with the nonreducing ends of the two branches anchored at the two primary binding sites, providing a structural explanation for the lectin's specificity for branched alpha-mannans. A comparison of the dimeric banana lectin with other beta-prism I fold lectins, provides interesting insights into the variability in their quaternary structure. 相似文献
6.
Ronan M. Kelly Lubbert Dijkhuizen Hans Leemhuis 《Applied microbiology and biotechnology》2009,84(1):119-133
Cyclodextrin glucanotransferases (CGTases) have attracted major interest from industry due to their unique capacity of forming
large quantities of cyclic α-(1,4)-linked oligosaccharides (cyclodextrins) from starch. CGTases produce a mixture of cyclodextrins
from starch consisting of 6 (α), 7 (β) and 8 (γ) glucose units. In an effort to identify the structural factors contributing
to the evolutionary diversification of product specificity amongst this group of enzymes, we selected nine CGTases from both
mesophilic, thermophilic and hyperthermophilic organisms for comparative product analysis. These enzymes displayed considerable
variation regarding thermostability, initial rates, percentage of substrate conversion and ratio of α-, β- and γ-cyclodextrins
formed from starch. Sequence comparison of these CGTases revealed that specific incorporation and/or substitution of amino
acids at the substrate binding sites, during the evolutionary progression of these enzymes, resulted in diversification of
cyclodextrin product specificity.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Hans Leemhuis acknowledges financial support from the Netherlands Organization for Scientific Research (NWO). 相似文献
7.
V. E. Piskarev T. L. Bushueva I. A. Yamskov 《Russian Journal of Bioorganic Chemistry》2007,33(1):170-174
We studied interaction of the lectin from the bark of Golden Rain shrub (Laburnum anagyroides, LABA) with a number of basic fucose-containing carbohydrate antigens by changes in its tryptophan fluorescence. The strongest LABA binding was observed for the trisaccharide H of type 6 [α-L-Fucp-(1-2)-β-D-Galp-(1-4)-D-Glc, K a = 4.2 × 103 M?1]. The following antigens were bound with a weaker affinity: H-disaccharide α-L-Fucp-(1-2)-D-Gal, a glucoanalogue of tetrasaccharide Ley α-L-Fucp-(1-2)-β-D-Galp-(1-4)-[α-L-Fucp-(1-3)]-D-Glc, and 6-fucosyl-N-acetylglucosamine, a fragment of core of the N-glycans family (K a 1.1?1.7 × 103 M?1). The lowest binding was observed for L-fucose (K a = 2.7 × 102 M?1) and trisaccharide Lea, (β-Galp-(1-3)-[α-L-Fucp-(1-4)]-GlcNAc (K a = 6.4 × 102 M?1). The Led, Lea, and Lex pentasaccharides and Leb hexasaccharide were not bound to LABA. 相似文献
8.
Various monosaccharides and oligosaccharides were used to define the specificity of theButea frondosa lectin using the hapten inhibition technique of human erythrocyte agglutination. AlthoughB. frondosa lectin exhibited higher affinity forN-acetylgalactosamine, lactose andN-acetyllactosamine appeared to be relatively good inhibitors of haemagglutination. The behaviour ofN-acetyllactosamine-type oligosaccharides and glycopeptides on a column ofB. frondosa lectin immobilized on Sepharose 4B showed that the sugar-binding specificity of the lectin is directed towards unmaskedN-acetyllactosamine sequences. Substitution of theseN-acetyllactosamine sequences by sialic acid residues completely abolished the affinity of the lectin for the saccharides. The presence of one or several Fuc(1-3)GlcNAc groups completely inhibited the interaction between the glycopeptides and the lectin. Substitution of the core -mannose residue by an additional bisecting (1-4)GlcNAc residue decreases the affinity of the lectin for these structures as compared with the unsubstituted ones. 相似文献
9.
Wu AM Singh T Liu JH Krzeminski M Russwurm R Siebert HC Bonvin AM André S Gabius HJ 《Glycobiology》2007,17(2):165-184
10.
Yuko Taniguchi 《European journal of applied physiology and occupational physiology》1997,75(2):144-150
Maximal voluntary strength of simultaneous bilateral exertion has been shown to be small compared to the sum of the unilateral
exertions. Three experiments were conducted to determine the effects of bilateral and unilateral resistance training on this
bilateral deficit and to compare these in hands, arms, and legs. In each experiment, the subjects were divided into three
groups: unilateral training group, bilateral training group, and control group. The subjects of the training group performed
maximal isometric handgrip training in experiment I, and maximal isokinetic arm and leg extension training in experiments
II and III. In each experiment, the subjects of the training group continued one of these resistance training exercises three
times a week, for 6 weeks. The increase in handgrip strength of the bilateral training group produced in the bilateral condition
[5.1 (SEM 2.4)%, after 3 weeks, 6.4 (SEM 2.3) %, after 6 weeks] was significantly greater compared with the control group
[−1.1 (SEM 1.0) %, after 3 weeks, −1.5 (SEM 1.1) %, after 6 weeks. The increase in leg extension power of the bilateral training
group produced in the bilateral condition [16.1 (SEM 9.6) %, after 3 weeks, 24.1 (SEM 7.4) %, after 6 weeks] was significantly
greater compared with the unilateral training group [−5.0 (SEM 3.4) %, after 3 weeks, −3.4 (SEM 4.2) %, after 6 weeks] and
the control group [−4.3 (SEM 2.5) %, after 3 weeks, 1.5 (SEM 5.5) %, after 6 weeks]. The increase in handgrip strength of
the unilateral training group produced in the unilateral condition [7.3 (SEM 1.7) %, after 3 weeks] was significantly greater
compared with the control group [−0.9 (SEM 1.8) %, after 3 weeks]. The increase in arm extension power of the unilateral training
group produced in the unilateral condition [7.2 (SEM 1.8) %, after 6 weeks] was significantly greater compared with the bilateral
training group [−3.0 (SEM 2.3) %, after 6 weeks] and the control group [−2.1 (SEM 2.6) %, after 6 weeks]. Bilateral indexes
(BI) were shifted in a positive direction by bilateral training and tended to shift in a negative direction by unilateral
training. With regard to the magnitude of change in BI, there were no significant differences among handgrip, arm extension,
and leg extension training. It is suggested that there is lateral specificity in resistance training and that there is no
difference among body parts in the modification of bilateral deficit by lateral training.
Accepted: 27 August 1996 相似文献
11.
Remy Loris Florence Casset Julie Bouckaert Jurgen Pletinckx Minh-Hoa Dao-Thi Freddy Poortmans Anne Imberty Serge Perez Lode Wyns 《Glycoconjugate journal》1994,11(6):507-517
The X-ray crystal structure of lentil lectin in complex with -d-glucopyranose has been determined by molecular replacement and refined to anR-value of 0.20 at 3.0 Å resolution. The glucose interacts with the protein in a manner similar to that found in the mannose complexes of concanavalin A, pea lectin and isolectin I fromLathyrus ochrus. The complex is stabilized by a network of hydrogen bonds involving the carbohydrate oxygens O6, O4, O3 and O5. In addition, the -d-glucopyranose residue makes van der Waals contacts with the protein, involving the phenyl ring of Phe123. The overall structure of lentil lectin, at this resolution, does not differ significantly from the highly refined structures of the uncomplexed lectin.Molecular docking studies were performed with mannose and its 2-O and 3-O-m-nitro-benzyl derivatives to explain their high affinity binding. The interactions of the modelled mannose with lentil lectin agree well with those observed experimentally for the protein-carbohydrate complex. The highly flexible Me-2-O-(m-nitro-benzyl)--d-mannopyranoside and Me-3-O-(m-nitro-benzyl)--d-mannopyranoside become conformationally restricted upon binding to lentil lectin. For best orientations of the two substrates in the combining site, the loss of entropy is accompanied by the formation of a strong hydrogen bond between the nitro group and one amino acid, Gly97 and Asn125, respectively, along with the establishment of van der Waals interactions between the benzyl group and the aromatic amino acids Tyr100 and Trp128.RL and FC are joint first authors. 相似文献
12.
The behaviour ofN-acetyllactosamine-type oligosaccharides and glycopeptides on a column of mistletoe lectin I (MLI) immobilized on Sepharose 4B was examined. The immobilized lectin does not show any affinity for asialo-N-glycosylpeptides and related oligosaccharides, which possess one to four unmaskedN-acetyllactosamine sequences. However, substitution of at least one of theN-acetyllactosamine sequences by sialic acid residues, either at O-3 or O-6 of galactose, slightly enhances the affinity of the lectin. Such sialylatedN-glycosylpeptides or oligosaccharides are eluted from the lectin column by the starting buffer as retarded fractions. Surprisingly, the affinity of the immobilized MLI is higher for P1 antigen-containing glycopeptide isolated from turtle-dove ovomucoid and for glycopeptides from bovine thyroglobulin containing terminal non-reducing Gal1–3Gal sequences. These structures are strongly bound on the lectin column and their elution is obtained with 0.15M galactose in the starting buffer.In memory of Hartmut Franz. 相似文献
13.
14.
M. Mercedes Iglesias Gisela D. Cymes Carlota Wolfenstein-Todel 《Glycoconjugate journal》1996,13(6):967-976
A sialic-acid-specific lectin from ovine placental cotyledons was purified by affinity chromatography on bovine submaxillary mucin-agarose followed by gel filtration, and it showed a molecular weight of 65 000 by sodium dodecylsulfate-polyacrylamide gel electrophoresis. This lectin has the capacity to interact with actin, since in binds to actin-F in a cosedimentation assay and it acts as a mediator in the binding of action to the affinity column. The lectin agglutinated rabbit and rat erythrocytes, but not human A, B or O erythrocytes. Haemagglutination inhibition assays of different saccharides, glycoproteins and glycolipids indicate that this lectin has affinity for sialic acid, which is enhanced by its O-acetylation. The N-terminal sequence of the protein shows 92% identity with rabbit and porcine uterine calreticulin. 相似文献
15.
Summary. The proton coupled amino acid transporter PAT1 expressed in intestine, brain, and other organs accepts L- and D-proline, glycine,
and L-alanine but also pharmaceutically active amino acid derivatives such as 3-amino-1-propanesulfonic acid, L-azetidine-2-carboxylic
acid, and cis-4-hydroxy-D-proline as substrates. We systematically analyzed the structural requirements for PAT1 substrates
by testing 87 amino acids, proline homologs, indoles, and derivatives. Affinity data and effects on membrane potential were
determined using Caco-2 cells. For aliphatic amino acids, a blocked carboxyl group, the distance between amino and carboxyl
group, and the position of the hydroxyl group are affinity limiting factors. Methylation of the amino group enhances substrate
affinity. Hetero atoms in the proline template are well tolerated. Aromatic α-amino acids display low affinity. PAT1 interacts
strongly with heterocyclic aromatic acids containing an indole scaffold. The structural requirements of PAT1 substrates elucidated
in this study will be useful for the development of prodrugs. 相似文献
16.
17.
The structure of the methyl-alpha-D-mannopyranoside-LOL I complex has been solved by the molecular replacement method using the refined saccharide-free LOL I coordinates as starting model. The methyl-alpha-D-mannopyranoside-LOL I complex was refined by simulated annealing using the program X-PLOR. The final R-factor value is 0.182 [Fo greater than 1 sigma(Fo)]. The isostructural methyl-alpha-D-glucopyranoside-LOL I complex was refined by X-Ray coupled energy minimization using the methyl-alpha-D-mannopyranoside-LOL I structure as a starting model to an R factor of 0.179 (all data). In both crystal forms, each dimer binds two molecules of sugar in pockets found near the calcium ions. The two saccharide moieties, which are in the C1 chair conformation, establish the same hydrogen bond pattern with the lectin. However, the van der Waals contacts are different between the O2, C2, C6, and O6 atoms of the two molecules and the backbone atoms of residues 208-211. Mannose, due to its axial C2 conformation, encloses the backbone atoms of the protein in a clamplike way. Van der Waals energy calculations suggest that this better complementarity of the mannoside molecule with the lectin could explain its higher affinity for isolectin I. 相似文献
18.
Lannoo N Vandenborre G Miersch O Smagghe G Wasternack C Peumans WJ Van Damme EJ 《Plant & cell physiology》2007,48(8):1207-1218
Previous experiments with tobacco (Nicotiana tabacum L. cv Samsun NN) plants revealed that jasmonic acid methyl ester (JAME) induces the expression of a cytoplasmic/nuclear lectin in leaf cells and provided the first evidence that jasmonates affect the expression of carbohydrate-binding proteins in plant cells. To corroborate the induced accumulation of relatively large amounts of a cytoplasmic/nuclear lectin, a detailed study was performed on the induction of the lectin in both intact tobacco plants and excised leaves. Experiments with different stress factors demonstrated that the lectin is exclusively induced by exogeneously applied jasmonic acid and JAME, and to a lesser extent by insect herbivory. The lectin concentration depends on leaf age and the position of the tissue in the leaf. JAME acts systemically in intact plants but very locally in excised leaves. Kinetic analyses indicated that the lectin is synthesized within 12 h exposure time to JAME, reaching a maximum after 60 h. After removal of JAME, the lectin progressively disappears from the leaf tissue. The JAME-induced accumulation of an abundant nuclear/cytoplasmic lectin is discussed in view of the possible role of this lectin in the plant. 相似文献
19.
M. Fernanda Troncoso M. Mercedes Iglesias Rainer Isecke Carlota Wolfenstein Todel Reinhard Brossmer 《Glycoconjugate journal》2000,17(10):705-711
The specificity of the sialic acid-binding lectin from ovine placenta was examined in detail by haemagglutination inhibition assays applying a panel of 32 synthetic sialic acid analogues. The carboxylic acid group is a prerequisite for the interaction with the lectin, the -anomer of the methyl glycoside is only a little more effective as an inhibitor than the -anomer and the most potent inhibitor was 9-deoxy-10-carboxylic acid Neu5Ac, followed by 4-oxo-Neu5Ac. In contrast to the majority of known sialic acid-binding lectins, the N-acetyl group of Neu5Ac is not indispensable for binding, neither is the hydroxyl group at C-9 since substitutions at this carbon atom are well tolerated. Furthermore, all sulfur-containing substituents at C-9 enhanced the affinity of the lectin. This is the first sialic acid-binding lectin found to strongly bind thio derivatives. 相似文献