Structure of a lectin with antitumoral properties in king bolete (Boletus edulis) mushrooms.

A novel lectin has been isolated from the fruiting bodies of the common edible mushroom Boletus edulis (king bolete, penny bun, porcino or cep) by affinity chromatography on a chitin column. We propose for the lectin the name BEL (B. edulis lectin). BEL inhibits selectively the proliferation of several malignant cell lines and binds the neoplastic cell-specific T-antigen disaccharide, Galβ1-3GalNAc. The lectin was structurally characterized: the molecule is a homotetramer and the 142-amino acid sequence of the chains was determined. The protein belongs to the saline-soluble family of mushroom fruiting body-specific lectins. BEL was also crystallized and its three-dimensional structure was determined by X-ray diffraction to 1.15 Å resolution. The structure is similar to that of Agaricus bisporus lectin. Using the appropriate co-crystals, the interactions of BEL with specific mono- and disaccharides were also studied by X-ray diffraction. The six structures of carbohydrate complexes reported here provide details of the interactions of the ligands with the lectin and shed light on the selectivity of the two distinct binding sites present in each protomer

Purification and characterization of a new lectin from the edible mushroom Boletus edulis with antiproliferative effect on tumor cell lines

A new lectin was isolated from the fruiting bodies of the ediblemushroom Boletus edulis by affinity chromatography on a chitincolumn. Boletus edulis lectin (BEL) exhibited a molecular mass ofapproximately 15 kDa in SDS-PAGE under reducing conditions.BEL cDNA was cloned and the deduced primary sequence,corresponding to 142 amino acids and a calculated molecular massof 15597 Da, showed a high similarity with the members of thefungal saline-soluble lectin family. The binding properties of thelectin were studied by competitive enzyme-lectin assays (CELA).The results show, as it was previously described for the Agaricusbisporus lectin (ABL), that BEL would have two sugar bindingsites with different specificity, one for Thomsen Friedenreich antigen(TF antigen, Gal\u3b21-3GalNAc\u3b1-O-Ser/Thr) related residues and theother for N-acetyl glucosamine. The lectin also exhibited a potentdose-dependent antiproliferative activity toward some human tumorcell lines with no apparent cytotoxicity

Crystal structure and ligand selectivity of the antineoplastic lectin from the common edible mushroom (Agaricus bisporus)

The lectin from the common mushroom Agaricus bisporus, the most popular edible species in western countries, has potent antiproliferative effects on human epithelial cancer cells without any apparent cytotoxicity. This property confers to it an important therapeutic potential as an antineoplastic agent. The threedimensional structure of the lectin was determined by X-ray diffraction. The protein is a tetramer with 222 symmetry and each monomer presents a novel fold with two beta sheets connected by a helix-loop-helix motif. Selectivity was studied by examining the binding of four monosacharides and seven disaccharides in two different crystal forms. The T-antigen disaccharide, Gal\u3b21- 3GalNAc, binds at a shallow depression on the surface of the molecule. The binding of N-acetylgalactosamine overlaps with that moiety of the T-antigen but surprisingly, N-acetylglucosamine binds at a totally different site on the opposite side of the helix-loophelix motif. The lectin has thus two distinct binding sites per monomer that recognize the different configuration of a single epimeric hydroxyl

Structure and properties of the C-terminal domain of insulin-like growth factor-binding protein-1 isolated from human amniotic fluid.

Insulin-like growth factor (IGF)-binding protein-1 (IGFBP- 1) regulates the activity of the insulin-like growth factors in early pregnancy and is, thus, thought to play a key role at the fetal-maternal interface. The C-terminal domain of IGFBP-1 and three isoforms of the intact protein were isolated from human amniotic fluid, and sequencing of the four N-terminal polypeptide chains showed them to be highly pure. The addition of both intact IGFBP-1 and its C-terminal fragment to cultured fibroblasts has a similar stimulating effect on cell migration, and therefore, the domain has a biological activity on its own. The three-dimensional structure of the Cterminal domain was determined by x-ray crystallography to 1.8 Å resolution. The fragment folds as a thyroglobulin type I domain and was found to bind the Fe2 ion in the crystals through the only histidine residue present in the polypeptide chain. Iron (II) decreases the binding of intact IGFBP-1 and the C-terminal domain to IGF-II, suggesting that the metal binding site is close to or part of the surface of interaction of the two molecules

Bromine isotope ratio measurements in seawater by multi-collector inductively coupled plasma-mass spectrometry with a conventional sample introduction system

A simple and accurate methodology for Br isotope ratio measurements in seawater by multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS) with pneumatic nebulization for sample introduction was developed. The Br+ signals could be measured interference-free at high mass resolution. Memory effects for Br were counteracted using 5 mmol L-1 of NH4OH in sample, standard, and wash solutions. The major cation load of seawater was removed via cation exchange chromatography using Dowex 50WX8 resin. Subsequent Br preconcentration was accomplished via evaporation of the sample solution at 90 °C, which did not induce Br losses or isotope fractionation. Mass discrimination was corrected for by external correction using a Cl-matched standard measured in a sample-standard bracketing approach, although Sr, Ge, and Se were also tested as potential internal standards for internal correction for mass discrimination. The δ81Br (versus standard mean ocean bromide (SMOB)) values thus obtained for the NaBr isotopic reference material NIST SRM 977 and for IRMM BCR-403 seawater certified reference material are in agreement with literature values. For NIST SRM 977, the 81Br/79Br ratio (0.97291) was determined with a precision ≤0.08‰ relative standard deviation (RSD).A simple and accurate methodology for Br isotope ratio measurements in seawater by multi-collector inductively coupled plasma-mass spectrometry (MC-ICP-MS) with pneumatic nebulization for sample introduction was developed. The Br+ signals could be measured interference-free at high mass resolution. Memory effects for Br were counteracted using 5 mmol L-1 of NH4OH in sample, standard, and wash solutions. The major cation load of seawater was removed via cation exchange chromatography using Dowex 50WX8 resin. Subsequent Br preconcentration was accomplished via evaporation of the sample solution at 90 A degrees C, which did not induce Br losses or isotope fractionation. Mass discrimination was corrected for by external correction using a Cl-matched standard measured in a sample-standard bracketing approach, although Sr, Ge, and Se were also tested as potential internal standards for internal correction for mass discrimination. The delta Br-81 (versus standard mean ocean bromide (SMOB)) values thus obtained for the NaBr isotopic reference material NIST SRM 977 and for IRMM BCR-403 seawater certified reference material are in agreement with literature values. For NIST SRM 977, the Br-81/Br-79 ratio (0.97291) was determined with a precision a parts per thousand currency sign0.08aEuro degrees relative standard deviation (RSD)