Purification, Characterization, Molecular Clone And Expression Of Typhonium Divaricatum (L.) Decne Agglutinin

A lectin named TDA was isolated by chromatography and some other methods from the rhizomes of Typhonium divaricatum(L.) Decne, a plant used as traditional chinese herbal medicine. TDA could agglutinate rabbit erythrocytes and the lowest agglutination concentration was 0.95 μg/ml; The apparent Mr of TDA was 48 KD and considered to be a tetrameric protein with four subunits. Isoelectric focusing showed that TDA was an acidic protein with pI of about 4.5 and 6.5. The result of hemagglutinating inhibition tests showed that Mannan, Ovomucoid , Asialoglycoproteins and Thyroglobulin could inhibit the agglutinating activity of TDA, so TDA was a mannose-binding lectin.The change of agglutinating activity of TDA in different temperature and pH indicated that TDA was a comparatively stable protein to temperature and pH. Metal ion was not helpful to hemagglutination activity of TDA.Fluorescence quenching study on TDA with CsCl, KI and acrylamide showed that they quenched the fluorescence of TDA through dynamic quenching mechanism, and 100% of Trp were quenched by acrylamide, 83.3 %of Trp were quenched by Ki and 50% of Trp were quenched by CsCl. It's indicated that most of Trp in TDA was exposed to the surface of molecule, just only a little was embedded in the core of protein,,The conformation changes of TDA in the presence of different...