title: Purification and characterization of a novel lectin from Chinese leek seeds.
abstract: A novel lectin, CLSL, was purified from Chinese leek seeds by ion exchange chromatography on SP Sephadex C-25 and gel filtration chromatography on Sephadex G50. The lectin had a molecular weight of 23.6 kDa and was composed of two identical subunits linked by disulfide bonds, a conclusion based on SDS-PAGE under reducing and nonreducing conditions. CLSL was a glycoprotein with a carbohydrate content of 3.6%. It exerted potent agglutinating activity against rat red blood cells at a concentration of 8.9 μg/mL. Hemagglutination of rat erythrocytes was inhibited by d-fructose, mannitol, and sorbose at the concentration of 20 mM. The hemagglutinating activity of CLSL was maintained at 100 °C for 60 min and under acidic pH conditions but was lost at neutral and alkaline pH conditions. The hemagglutinating activity was stimulated by Ca(2+), Fe(2+), and Cu(2+) but inactivated by Ba(2+) at a concentration of 10 mM. Ba(2+)-mediated inactivation of CLSL was caused by CLSL conformational change induced by barium ions, according to the results of circular dichroism and fluorescence spectroscopy. Deconvolution of the CLSL circular dichroism indicated that it was an α-helical lectin with α-helix and β-fold contents of 35.8% and 8.6%, respectively. CLSL could also selectively inhibit cell proliferation.
authors.affiliation: College of Biological Science and Technology, Fuzhou University , 2 Xue Yuan Road, University Town, Fuzhou, Fujian 350108, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Hong
authors.forename: Tao-Tao
authors.initials: TT
authors.lastname: Chen
authors.forename: Lei
authors.initials: L
authors.lastname: Hu
authors.forename: Jie
authors.initials: J
authors.lastname: Yang
authors.forename: Pei
authors.initials: P
authors.lastname: Hu
authors.forename: Shao-Yun
authors.initials: SY
authors.lastname: Wang
mesh_terms: D000818:Animals; D004912:Erythrocytes / Q000187:drug effects; D006384:Hemagglutination / Q000187:drug effects; D006388:Hemagglutinins / Q000737:chemistry* / Q000302:isolation & purification* / Q000494:pharmacology; D037102:Lectins / Q000737:chemistry* / Q000302:isolation & purification* / Q000494:pharmacology; D019697:Onions / Q000737:chemistry*; D010940:Plant Proteins / Q000737:chemistry* / Q000302:isolation & purification* / Q000494:pharmacology; D051381:Rats; D012639:Seeds / Q000737:chemistry*
chemical_list: D006388:Hemagglutinins; D037102:Lectins; D010940:Plant Proteins
keywords: Chinese leek seeds; circular dichroism; fluorescence spectroscopy; lectin; purification