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PubMed1986

[Lectin receptors in the salivary glands of the rat during postnatal ontogenesis].

Distribution of lectin-binding sites in rat submandibular and sublingual salivary glands during postnatal development has been investigated. Lectin preparations include con A, lentin lectin, castor beans agglutinin, peanut, soybean and Sophora japonica agglutinins, wheat germ agglutinin and lectin from the bark of Laburnum anagyroides. The direct and indirect peroxidase techniques are used. According to the similarities of histochemical patterns, all lectins are divided into four groups. Besides the general patterns of lectin binding sites, some details are noted. Lectins of peanut and Sophora japonica possess an extremely high affinity to mast cells, con A, lens lectin, castor beans and wheat germ agglutinins--to serous demilunes cells. Laburnum lectin--to salivary ducts epithelia in adult rat salivary glands. Lentin lectin, con A and Laburnum lectin preferentially stain cells with specific granularity in granular ducts at early stages of postnatal development. Considering the character of staining, we propose for further histochemical investigations of the salivary glands lentin lectin, peanut agglutinin, wheat germ agglutinin and Laburum anagyroides lectin.

Animals↗
PubMed2000

Cloning and characterization of a monocot mannose-binding lectin from Crocus vernus (family Iridaceae).

The molecular structure and carbohydrate-binding activity of the lectin from bulbs of spring crocus (Crocus vernus) has been determined unambiguously using a combination of protein analysis and cDNA cloning. Molecular cloning revealed that the lectin called C. vernus agglutinin (CVA) is encoded by a precursor consisting of two tandemly arrayed lectin domains with a reasonable sequence similarity to the monocot mannose-binding lectins. Post-translational cleavage of the precursor yields two equally sized polypeptides. Mature CVA consists of two pairs of polypeptides and hence is a heterotetrameric protein. Surface plasmon resonance studies of the interaction of the crocus lectin with high mannose-type glycans showed that the lectin interacts specifically with exposed alpha-1,3-dimannosyl motifs. Molecular modelling studies confirmed further the close relationships in overall fold and three-dimensional structure of the mannose-binding sites of the crocus lectin and other monocot mannose-binding lectins. However, docking experiments indicate that only one of the six putative mannose-binding sites of the CVA protomer is active. These results can explain the weak carbohydrate-binding activity and low specific agglutination activity of the lectin. As the cloning and characterization of the spring crocus lectin demonstrate that the monocot mannose-binding lectins occur also within the family Iridaceae a refined model of the molecular evolution of this lectin family is proposed.

Agglutinins↗
PubMed1987

Comparative analysis of galactoside-binding lectins isolated from mammalian spleens.

Galactoside-inhibitable lectins have been isolated from rabbit, rat, mouse, pig, lamb, calf, and human spleens. Native molecular mass, subunit structure, pI, and hemagglutinating activity have been compared for these lectins. The yields of lectin varied from 1.8 mg/kg for rabbit spleen to 79 mg/kg for lamb spleen. Pig, lamb, calf, and human spleen lectins yielded single protein peaks when subjected to Superose 12 fast-protein liquid chromatography. The apparent molecular mass for these lectins was 33-34 kDa. In contrast, rat and mouse spleen lectin preparations were separated into three components ranging from 8.4 to 34 kDa. Superose 12 chromatography of rabbit spleen lectin revealed the presence of at least six components. Gradient slab gel sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed the presence of single polypeptides for pig, calf, lamb, and human lectins corresponding to a molecular mass of 14-14.5 kDa. Multiple polypeptides were detected for the mouse, rat, and rabbit lectins. The molecular mass of the major polypeptides were 15, 15, and 17 kDa for rat, mouse, and rabbit, respectively. The presence of isolectins in all preparations was shown by isoelectric focusing. The major isolectins were acidic proteins with pI 4.38-4.80. Hemagglutination and hemagglutination inhibition assays demonstrated similarities as well as differences among the lectin preparations. Hemagglutinating activity could not be demonstrated in rabbit spleen extracts nor for isolated putative lectin. Human buffy coat cells were reversibly agglutinated by calf and human spleen lectins, demonstrating the presence of leucocyte cell surface lectin receptors.

Animals↗
PubMed1989

Isolation and characterization of soluble beta-galactoside-binding lectins from mammalian liver.

Soluble beta-galactoside-binding lectins were isolated by chromatography on asialofetuin-Sepharose-4B column in 10 mM Tris-HCl buffer (pH 7.5) containing 150 mM NaCl, 5 mM CaCl2 and 1 mM 2-mercaptoethanol. The three lectins moved essentially as single polypeptide bands, of 18, 22 and 24 kDa, respectively, for sheep, goat and buffalo hepatic lectins. Sheep and goat lectins each contained 4 mol of hexose, whereas the hexose content of the buffalo lectin was 7 mol. The number of sulfhydryl groups in sheep, goat and buffalo lectins were determined to be 3.2, 4.3 and 4.8, respectively. The optical properties of the three lectins were similar to those of tryptophan-containing proteins. Lectin-mediated hemagglutination of trypsinized rabbit erythrocytes was most effectively inhibited by lactose, followed by o-nitrophenyl beta-galactopyranoside and galactose, but remained unaffected by glucose, mannose, fucose and fructose. Calcium ions substantially enhanced their hemagglutinating activity. Goat and buffalo lectins, but not sheep lectin, were also stimulated by Mg2+, Mn2+, Sr2+ and Ni2+ ions. The lectins lost activity after treatment with para-hydroxy-mercuribenzoate and N-ethylmaleimide. However, iodoacetamide treatment had no effect on the activity. The results show that the three lectins are different from the soluble beta-galactoside-binding lectins studied thus far.

Animals↗
PubMed1988

Sequence of a full-length cDNA for rat lung beta-galactoside-binding protein: primary and secondary structure of the lectin.

A full-length cDNA for rat lung beta-galactoside lectin (subunit Mr approximately 14,000, lectin 14K) was cloned and the nucleotide sequence determined. The deduced amino acid sequence agrees with the amino acid composition and direct amino acid sequence analysis of purified rat lung lectin peptides. We found that the amino-terminal alanine is blocked with an acetyl group. Comparison of the amino acid sequence with other proteins shows a high degree of homology only with other vertebrate lectin sequences, supporting the suggestion that these lectins may constitute a unique class of vertebrate proteins. The amino acid composition and sequence of lectin peptides, the sequence of lectin cDNA, and isoelectric focusing of purified lectin indicate that rat lung lectin 14K is composed predominantly of a single protein. In addition, rat uterus lectin 14K was found to be the same protein as that present in lung. We characterized the secondary and tertiary structure of rat lung lectin 14K by circular dichroism, by analytical ultracentrifugation, and by computer analysis of its primary structure. Results of these experiments suggest that lectin 14K is primarily a hydrophilic protein with an asymmetric, elongated structure consisting of approximately equal amounts of alpha helix, beta sheet, beta turn, and random coil. We found that Cys-2 and Cys-130 react most rapidly with iodoacetamide; one or both of these residues may be primarily responsible for the thiol requirement of lectin activity.

Amino Acid Sequence↗
PubMed1981

Examination of Le and lele Genotypes of Glycine max (L.) Merr. for Membrane-Bound and Buffer-Soluble Soybean Lectin.

Membrane fractions from seedlings of four soybean [Glycine max (L.) Merr.] lines were examined by radioimmunoassay and hemagglutination assay for the 120,000 dalton soybean lectin. Two of the lines (Sooty and T-102) are genotypically lele and lack buffer-soluble soybean lectin; the remaining two lines (Beeson and Harosoy 63) are Le and produce seeds that contain the lectin (Su et al. 1980 Biochim. Biophys. Acta 629: 292-304). Both Triton X-100 (0.5% v/v) and nonidet P-40 (0.05% v/v) solubilized soybean lectin from membrane fractions of Le cotyledons. Triton X-100 interfered substantially with the assay of protein and hemagglutinating activity and was unacceptable for use in quantitative measurements. The nonidet P-40-solubilized soybean lectin from Le cotyledons was consistently present both in washed 13,000g and 82,500g membrane fractions, but it accounted for less than 1.5% of the total (buffer-soluble plus membrane-bound) soybean lectin. The membrane lectin was purified by the affinity chromatography procedure devised for soluble soybean lectin, and it was immunologically indistinguishable from authentic soybean lectin. Membrane fractions from Le cotyledons contained insignificant amounts of radioisotope-labeled soybean lectin that had been added during homogenization, and purified membrane fractions did not bind the lectin in the presence of the hapten, d-galactose. These controls make it unlikely that the membrane soybean lectin was of cytoplasmic origin. Soybean lectin and other hemagglutinins were not present in buffer-soluble or membrane fractions from lele cotyledons or from roots and hypocotyls of any of the lines.

Journal Article↗
PubMed1987

Distribution of an endogenous beta-galactoside-specific lectin during foetal and neonatal rabbit development.

The tissue concentration of an endogenous beta-galactoside-specific lectin is developmentally regulated in rabbit tissues during foetal and neonatal development. Immunoassay data and localization studies both indicate that the lectin is particularly associated with late embryonic and early postnatal development. No lectin could be detected in embryos prior to 21 days of gestation, whereas many tissues showed an increase in lectin around the time of birth. It is likely that in most tissues the high concentrations of lectin are largely due to increased synthesis by fibroblasts, which are particularly abundant and active in connective tissue during the extensive tissue reorganization taking place at this time. The lectin appears to be synthesized by other differentiated cell types also, notably myoblasts, alveolar cells and erythroblasts. The peak of lectin concentration seen in foetal liver probably reflects lectin associated with foetal erythropoiesis. The rabbit lectin has a low specific activity but its tissue concentration is correspondingly higher than lectin concentrations in other mammals. This conservation of total lectin activity suggests a fundamental role for the lectin dependent upon its saccharide binding activity. This and other indirect evidence suggests that these lectins are involved in the synthesis, secretion or organization of extracellular matrix components.

Animals↗
PubMed2001

Purification of Cajanus cajan root lectin and its interaction with rhizobial lipopolysaccharide as studied by different spectroscopic techniques.

A lectin present in roots of Cajanus cajan seedlings was isolated and purified by affinity chromatography. Sugar specificity assayed by hemagglutination-inhibition activity indicated that lectin belongs to glucose/mannose-specific group. The root lectin was found to be mannose-specific from the second day onwards as it was reconfirmed by specific elution of different days' sample from mannose agarose matrix. The maximum interaction of lectin with goat IgM was obtained in 10-day-old sample, indicating the highest crude lectin content. Lectin (total amount of eluted protein) from different days soil sample showed a maximum amount in 10-day-old sample. For further studies, the lectin has been isolated from the roots of 10-day C. cajan seedlings and purified on mannose-CL agarose column by affinity chromatography. Lectin was found to be a dimer of 18.5-kDa subunit as revealed by SDS-PAGE. Tryptophan quenching fluorescence was studied for C. cajan root lectin. Secondary structure of C. cajan root lectin as studied by circular dichroism was found to be a typical beta-pleated sheet structure. The interaction of purified root lectin with C. cajan-specific rhizobial lipopolysaccharide and its inhibition by specific and nonspecific sugars was demonstrated by fluorescence and circular dichroism. Results discussed in this paper were studied for the first time by different spectroscopic methods, suggesting that C. cajan root lectin-lipopolysaccharide interaction is specific.

Cell Wall↗
PubMed1995

Carbohydrate-binding proteins (plant/human lectins and autoantibodies from human serum) as mediators of release of lysozyme, elastase, and myeloperoxidase from human neutrophils.

Analysis of cell surface glycosylation not only provides information about cell properties such as their state of differentiation or histogenetic lineage. The carbohydrate chains also provide potentially functional binding sites to endogenous carbohydrate-binding proteins. This interaction can elicit consequent signalling processes. Because of the importance of neutrophils in the host defence system, we monitored the effect of the binding of such sugar receptors to their cell surface on the release of the enzymatic activities of lysozyme, elastase, and myeloperoxidase. Besides the mannose-binding lectin concanavalin A and the immunomodulatory alpha/beta-galactoside-binding lectin from Viscum album L., three preparations of human sugar receptors - beta-galactoside-binding lectin (M(r) 14 kDa) and two affinity-purified polyclonal IgG fractions from serum with the capacity to recognize alpha- or beta-galactosides, respectively - were used. Two animal lectins from chicken liver and intestine that bind beta-galactosides, as well as the lectin-like human serum amyloid P component, were included in order to assess the importance of slight differences in ligand recognition. Cytochalasin B-enhanced enzyme release was invariably seen with the two plant lectins and the chicken liver beta-galactoside-binding lectin, but the related intestinal lectin did not increase enzyme release. The mammalian homologue of these avian lectins triggered lysozyme secretion, and the lactoside-binding IgG fraction enhanced the amount of extracellular elastase activity slightly but significantly. Thus, the actual lectin, not the nominal specificity of sugar receptors, is crucial for elucidation of responses. Due to the highly stimulatory activity of the two plant lectins, neutrophils from patients with non-cancerous diseases and from patients with lung cancer were monitored for the extent of lectin-mediated enzyme release. Only the concanavalin A-mediated reactivity of the neutrophils was associated with the type of disease.

Adult↗
PubMed1987

Isolation and characterization of a lectin from the roots of Dolichos biflorus.

A lectin has been isolated from the roots of 7-day-old Dolichos biflorus plants and has been compared with the D. biflorus seed lectin. The root lectin differs from the seed lectin in molecular weight, subunit stoichiometry, amino acid composition, amino terminal amino acid sequence, and isoelectric focusing pattern. However, the root lectin has in common with the seed lectin a specificity for N-acetyl-D-galactosamine, and upon denaturation the root lectin will react weakly with antiserum made to denatured seed lectin. Distribution studies of this lectin in germinating seedlings show that the highest levels of lectin are found in 1-day-old roots. Upon dissection and analysis of 7-day-old roots, the highest levels of the lectin are in the uppermost segment. In addition, isoforms of this lectin also exist in the stems and leaves of the plant.

Amino Acid Sequence↗
PubMed1987

Isolation, molecular and biological properties of a lectin from rice embryo: relationship with wheat germ agglutinin properties.

Rice lectin (Oryza sativa, var. Balilla 28) was purified from defatted embryos by aqueous acid extraction at pH 1.3 followed by ammonium sulfate precipitation between 2 and 4 M, affinity chromatography on agarose-p-aminophenyl-beta-D-N-acetylglucosamine, and gel filtration on AcA 54. The homogeneity of the lectin was checked by polyacrylamide gel electrophoresis, gel filtration, and immunodiffusion. The amino acid analysis revealed a high half-cystine content (9%) and a low aromatic and hydrophobic amino acid content. The lectin contained neither neutral carbohydrates nor amino sugars. The isoelectric point was estimated to be 8.1. The molecular weight of rice lectin was estimated to be 38,000. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions showed two polypeptides with Mr 19,000 and 15,000. The circular dichroism spectrum of rice lectin in far ultraviolet was characterized by a positive maximum at 228 nm and a negative band at 203 nm suggesting the presence of a beta-pleated sheet and the absence of alpha-helix. Rice lectin had no human blood group specificity and agglutinated rabbit erythrocytes more efficiently than erythrocytes from other animal species. Furthermore, agglutination was enhanced by trypsin treatment of erythrocytes. The erythroagglutinating activity was very high since the minimal concentration needed to agglutinate erythrocytes was 0.05 micrograms/ml. Although [methyl-3H]thymidine incorporation was stimulated in human lymphocytes, rice lectin could not be considered as a mitogenic lectin since it stimulated neither blast transformation nor lymphocyte proliferation. The saccharide specificity of rice lectin was related to N-acetylglucosamine and its oligomers: N,N',N"-triacetylchitotriose was the most powerful inhibitor. Furthermore, the N-acetylneuraminic acid was not a specific rice determinant. Finally, the double immunodiffusion method revealed a cross-reactivity between rice lectin and wheat germ agglutinin, indicating that these lectins were closely antigenically related. The analogies and differences between biological and immunological properties of rice lectin and wheat germ agglutinin are discussed and the possibility of their evolution from a common ancestor is put forward.

Amino Acids↗
PubMed1980

Circular dichroism tests on the effect of alkali on conformation of lectins.

The structural properties of eight lectins (agglutinins) were studied by the circular dichroism (CD) probe. The lectin from Maclura pomifera (osage orange seed) exhibited in the far-ultraviolet spectral zone a positive CD band centered at 201 nm, whereas the other lectins had positive bands at 195--198 nm. Structural transitions were effected by alkali, pH 9.6--11.9. Native M. pomifera lectin had a positive CD band also at 236 nm which shifted to the red and enhanced by alkali. Significant individual differences in resistance to the denaturing effect of alkali were observed even between the lectins the CD spectra of which were similar in neutral solutions. The CD spectrum of the lectin from Wistaria floribunda was similar to the CD spectrum of the Dolichos biflorus lectin, but the former was much less sensitive to alkali than the latter. The CD spectra of the native lectins from soybean (Glycine max) and the erythroagglutinin from kidney bean (Phaseolus vulgaris) also were similar, yet the former was denatured at pH 10.6--11.6, whereas the CD of the latter was affected very little. The tertiary structures of the lectins from D. biflorus, the Sophora japonica and the fucose binding lectin from Tetragonolobus purpureas were more sensitive to alkali than those of the other lectins. While the CD bands at 270--300 nm, related to the tyrosine and tryptophan chromophores are generally diminished on denaturation, in the D. biflorus and S. japonica lectins these bands were enhanced at pH 9.6--10.6. In more strongly alkaline solutions, a new CD band developed at 248--252 nm. The main polypeptide chain was more or less completely disorganized at the very high pH values.

Alkalies↗
PubMed1997

Isolation, characterization and molecular cloning of the mannose-binding lectins from leaves and roots of garlic (Allium sativum L.).

Two novel lectins were isolated from roots and leaves of garlic. Characterization of the purified proteins indicated that the leaf lectin ASAL is a dimer of two identical subunits of 12 kDa, which closely resembles the leaf lectins from onion, leek and shallot with respect to its molecular structure and agglutination activity. In contrast, the root lectin ASARI, which is a dimer of subunits of 15 kDa, strongly differs from the leaf lectin with respect to its agglutination activity. cDNA cloning of the leaf and root lectins revealed that the deduced amino acid sequences of ASAL and ASARI are virtually identical. Since both lectins have identical N-terminal sequences the larger Mr of the ASARI subunits implies that the root lectin has an extra sequence at its C-terminus. These results not only demonstrate that virtually identical precursor polypeptides are differently processed at their C-terminus in roots and leaves but also indicate that differential processing yields mature lectins with strongly different biological activities. Further screening of the cDNA library for garlic roots also yielded a cDNA clone encoding a protein composed of two tandemly arrayed lectin domains. Since the presumed two-domain root lectin has not been isolated yet, its possible relationship to the previously described two-domain bulb lectin could not be studied at the protein level.

Amino Acid Sequence↗
PubMed1998

Diocleinae lectins are a group of proteins with conserved binding sites for the core trimannoside of asparagine-linked oligosaccharides and differential specificities for complex carbohydrates.

The seed lectin from Dioclea grandiflora and jack bean lectin concanavalin A (ConA) are both members of the Diocleinae subtribe of Leguminosae lectins. Both lectins have recently been shown to possess enhanced affinities and extended binding sites for the trisaccharide, 3,6-di-O-(alpha-D-mannopyranosyl)-D-mannose, which is present in the core region of all asparagine-linked carbohydrates (Gupta, D., Oscarson, S., Raju, S., Stanley, P. Toone, E. J. and Brewer, C. F. (1996) Eur. J. Biochem. 242, 320-326). In the present study, the binding specificities of seven other lectins from the Diocleinae subtribe have been investigated by hemagglutination inhibition and isothermal titration microcalorimetry (ITC). The lectins are from Canavalia brasiliensis, Canavalia bonariensis, Cratylia floribunda, Dioclea rostrata, Dioclea virgata, Dioclea violacea, and Dioclea guianensis. Hemagglutination inhibition and ITC experiments show that all seven lectins are Man/Glc-specific and have high affinities for the core trimannoside, like ConA and D. grandiflora lectin. All seven lectins also exhibit the same pattern of binding to a series of monodeoxy analogs and a tetradeoxy analog of the trimannoside, similar to that of ConA and D. grandiflora lectin. However, C. bonariensis, C. floribunda, D. rostrata, and D. violacea, like D. grandiflora, show substantially reduced affinities for a biantennary complex carbohydrate with terminal GlcNAc residues, while C. brasiliensis, D. guianensis, and D. virgata, like ConA, exhibit affinities for the oligosaccharide comparable with that of the trimannoside. Thermodynamic data obtained by ITC indicate different energetic mechanisms of binding of the above two groups of lectins to the complex carbohydrate. The ability of the lectins to induce histamine release from rat peritoneal mast cells is shown to correlate with the relative affinities of the proteins for the biantennary carbohydrate.

Animals↗
PubMed1987

cDNA cloning and in vitro synthesis of the Dolichos biflorus seed lectin.

The Dolichos biflorus seed lectin contains two structurally related subunits. A cDNA library was constructed using RNA isolated from D. biflorus seeds actively synthesizing the seed lectin. The library was expressed in Escherichia coli using a lambda Charon 16 vector, and lectin-specific antiserum was used to isolate a seed lectin cDNA. Hybridization of the D. biflorus seed lectin cDNA to RNA isolated from seeds actively producing both lectin subunits identifies a single-size RNA of 1100 bases. An oligodeoxyribonucleotide probe, constructed from an amino acid sequence common to both lectin subunits, detects the same size RNA. Translation of seed mRNA in vitro and immunoprecipitation of translation products using a lectin-specific antiserum yields a single polypeptide of slightly higher molecular mass than the largest seed lectin subunit. This seed lectin precursor is indistinguishable from a polypeptide synthesized from mRNA hybrid selected by the seed lectin cDNA. These data support the existence of a single polypeptide precursor for both subunit types of the D. biflorus seed lectin and suggest that differences between the subunit types arise by posttranslational processing.

Amino Acid Sequence↗
PubMed1991

Purification and characterization of two types of Cytisus sessilifolius anti-H(O) lectins by affinity chromatography.

Two anti-H(O) lectins were separated from extracts of Cytisus sessilifolius seeds by successive affinity chromatographies on columns of di-N-acetylchitobiose- and galactose-Sepharose 4B. One was found to be inhibited most by di-N-acetylchitotriose or tri-N-acetylchitotriose [Cytisus-type anti-H(O) lectin designated as Cytisus sessilifolius lectin I (CSA-I)] and the other anti-H(O) lectin was inhibited by galactose or lactose and designated as Cytisus sessilifolius lectin II (CSA-II). These two anti-H(O) lectins were further purified by gel filtration on TSK-Gel G3000SW. These preparations were homogeneous as judged by polyacrylamide gel electrophoresis and gel filtration. The molecular masses of the purified lectins I and II were found to be 95,000 and 68,000 Da, respectively, by gel filtration on TSK-Gel G3000SW. On polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate and 2-mercaptoethanol, both lectins gave a single component of molecular masses of 27,000 +/- 2,000 and 34,000 +/- 2,000 Da, respectively, suggesting that the lectins I and II were composed of four and two apparently identical subunits, respectively. Lectins I and II contain 38% and 13% carbohydrate, respectively, and only very small amounts of cysteine and methionine, but they are rich in aspartic acid, serine and glycine. The N-terminal amino-acid sequences of these two lectins were determined and compared with those of several lectins already published.

Amino Acid Sequence↗
PubMed2001

cDNA cloning and sequence analysis of the lectin genes of the Korean mistletoe (Viscum album coloratum).

We previously isolated a lectin of the Korean mistletoe (Viscum album coloratum). The cDNA clones that encode the A- or the B-chain of the Korean mistletoe lectin were cloned by reverse transcriptase polymerase chain reaction (RT-PCR). The mRNAs that were extracted from the Korean mistletoe were amplified, ligated into the pGEM-T easy vector, and screened with a Korean mistletoe lectin-specific probe. The probe was prepared by PCR amplification of the Korean mistletoe DNA using a primer set designed on the basis of amino acid sequences of the Korean mistletoe lectin that we had purified and reported. Unlike a recent report, which states that the European mistletoe lectin gene has no isoforms, several different clones of the A- and B-chains of the Korean mistletoe lectin were cloned from the same primer set. Three clones of each were selected for sequencing. The sizes of the A-chains were 762, 762, and 768 bp, respectively. The B-chain sizes were 798, 789, and 789 bp, respectively. Each of the clones showed significant variation in the amino acids sequence, including the N-linked glycosylation sites of the lectin. The sequence analysis of each of the Korean lectin clones, in comparison with the European mistletoe lectin and the other type II ribosome binding proteins, is discussed in the text. In addition, Southern blot analysis of the Korean mistletoe genomic DNA, restricted by different enzymes and hybridized with the lectin DNA, showed multi-bands, supporting the existence of multicopy genes or a gene family. These data suggest that heterogeneity of the mistletoe lectin is not only introduced by post-translational modifications, but also by expression of isotypes of the lectin genes.

Amino Acid Sequence↗
PubMed1977

Lectins in the hemolymph of Japanese horseshoe crab, tachypleus tridentatus.

The hemolymph of the Japanese horseshoe crab, Tachypleus tridentatus contains lectins which agglutinate mammalian erythrocytes. Affinity chromatographic purification of the lectins using bovine submaxillary gland mucin-conjugated Sepharose resulted in the separation of the lectins into four fractions; one major and three minor lectins. Protein subunits revealed by polyacrylamide gel electrophoresis and the immunoprecipitin line of these lectins against antiserum to crude lectins were unique to each fraction. The activities of all the lectins were optimal at pH values between 6 and 8, and were destroyed by heating at 60 degrees C. Calcium chloride augumented the activities of three lectins, but the major lectin was not influenced by the salt. Bovine erythrocytes were not agglutinated by any of the lectins and comparative agglutination titers for other erythrocytes from various sources were different among these lectins. The activities of all the lectins were inhibited by N-acetylamino sugars. They were more effectively inhibited by glycoproteins which contain sialic acid.

Animals↗