부산대학교 도서관

A new lectin has been isolated from the coral Gerardia savaglia by affinity chromatography, using locust gum as an absorbent, and D-mannose as eluant. Final purification was achieved by Bio-Gel P300 gel filtration. The agglutinin is a protein composed of two polypeptide chains with a Mr of 14800; the two subunits are not linked by disulfide bond(s). The isoelectric point is 4.8, the amino acid composition is rich in the acidic amino acids aspartic acid and glutamic acid. The absorption maximum for the protein was at 276 nm; with a molar absorption coefficient of 1.27 × 105 M-1 cm-1. The lectin precipitated erythrocytes from humans (A, B and 0), sheep, rabbit and carp with a titer between 25 and 1010; the affinity constant for lectin binding to sheep red blood cells was 2.8 x 108 M1 and the number of binding sites, 3.2 × 105/cell. Ca2+ ions are required for full activity; the pH optimum lies in the range between 6 and 11. Inhibition experiments revealed that the lectin is specific for D-mannose. The lectin is mitogenic only for those spleen lymphocytes from mice which had been activated by lipopolysaccharide. An interesting feature of this lectin is its ability to bind to glycoproteins present in nuclei from CV-1 monkey kidney cells. The fluorescein-isothiocyanate-labelled lectin reacted with six polypeptides in the nuclear envelope from rat liver (Mr 190000, 115000,80000,62000,56000 and 42000) and with two polypeptides in the nuclear matrix or pore complex lamina fraction (Mr 190000 and 62000). The lectin inhibited the nuclear envelope mRNA translocation system in vitro, it is suggested that this effect is due to an interaction of the lectin with the nuclear glycoproteins gp190 and/or gp62. [ABSTRACT FROM AUTHOR]