A toxic thionin from Pyrularia pubera: purification, properties, and amino acid sequence.
A low-molecular-weight cytotoxic protein has been purified from Pyrularia pubera Michx. (Santalaceae). By comparison with the behavior of proteins of known molecular weight during Sephadex G-75 gel filtration and denaturing electrophoresis, a molecular weight of somewhat less than 6000 is indicated. Purification involves ammonium sulfate fractionation followed by either gel filtration on Sephadex G-75 or separation on a carboxymethyl cellulose CM52 column. At concentrations of 0.04 mg/ml the protein causes visible disruption of cultured mouse B16 melanoma cells. The complete amino acid sequence has been determined. The toxin contains 47 amino acids arranged as follows:Lys-Ser-Cys-Cys-Arg-Asn-Thr-Trp-Ala-Arg-Asn-C ys-Tyr-Asn-Val-Cys-Arg-Leu-Pro-Gly-Thr-Ile-Ser-Arg-Glu-Ile-Cys-Ala-Lys- Lys-Cys-Asp-Cys-Lys-Ile-Ile-Ser-Gly-Thr-Thr-Cys-Pro-Ser-Asp-Tyr-Pro-Ly s-OH. The protein is clearly a thionin, as shown by its close resemblance to the thionins from wheat and barley, to the viscotoxins from mistletoes, and to crambin.
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D023181:Antimicrobial Cationic Peptides; D002470:Cell Survival / Q000187:drug effects; D055598:Chemical Phenomena; D011232:Chemical Precipitation; D002621:Chemistry; D002850:Chromatography, Gel; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D003603:Cytotoxins / Q000302:isolation & purification*; D004591:Electrophoresis, Polyacrylamide Gel; D037102:Lectins; D008545:Melanoma; D051379:Mice; D010084:Oxidation-Reduction; D037121:Plant Lectins; D010940:Plant Proteins / Q000302:isolation & purification* / Q000633:toxicity; D010947:Plants, Toxic / Q000032:analysis*; D013056:Spectrophotometry, Ultraviolet
D000596:Amino Acids; D023181:Antimicrobial Cationic Peptides; D003603:Cytotoxins; D037102:Lectins; D037121:Plant Lectins; D010940:Plant Proteins; C044942:THI1 protein, Pyrularia pubera; C488038:viscotoxin