RESUMEN
The presence of typical plant-type N-glycans (eg, M3FX, Gn2M3FX, and Le(a)2M3FX) in mosses, ferns, and other organisms was examined to determine which plant initially acquired glycosyltransferases to produce plant-type N-glycans during organic evolution. No M3FX-type N-glycan was detected in lichens (Cladonia humilis) or in any one of the three preland plants Enteromorpha prolifera, Ulva pertusa Kjellman, and Chara braunii Gmelin. In Bryophyta, M3FX-type N-glycan was detected at trace amounts in Anthocerotopsida (hornworts) and at certain amounts in Bryopsida (mosses), but not in Hepaticopsida (liverworts). Le(a)2M3FX was detected in some Bryopsida of relatively high M3FX content. Most Tracheophyta (ferns and higher plants) contained the three typical M3FX-type glycans as the main N-glycans in different ratios. These results suggest that organisms acquired xylosyltransferase and fucosyltransferase during the development of mosses from liverworts, and that later all plants retained both enzymes. Bryopsida have also obtained galactosyltransferase and fucosyltransferase to synthesize the Le(a) antigen.
Asunto(s)
Briófitas/metabolismo , Helechos/metabolismo , Fucosa/metabolismo , Glicosiltransferasas/metabolismo , Polisacáridos/metabolismo , Xilosa/metabolismo , Evolución Biológica , Fucosiltransferasas/metabolismo , Pentosiltransferasa/metabolismo , Polisacáridos/análisis , Especificidad de la Especie , UDP Xilosa Proteína XilosiltransferasaRESUMEN
Recently I found that glycosidase inhibitors such as castanospermine, deoxynojirimycin, swainsonine, 2-acetamindo 2,3-dideoxynojirimycin, and deoxymannojirimycin change the N-glycan structure of root glycoproteins, and that the glucosidase inhibitors castanospermine and deoxynojirimycin suppress the growth of Raphanus sativus seedlings (Mega, T., J. Biochem., 2004). The present study undertook to see whether the growth suppression is due to the inhibition of glucose trimming in endoplasmic reticulum (ER). The study, using three glucosidase inhibitors, castanospermine, N-methyl deoxynojirimycin, and deoxynojirimycin, upon the growth of R. sativus foliage leaf, made clear that glucose trimming is indispensable for plant growth, because the inhibition of glucose trimming correlated with leaf growth. On the other hand, processing inhibition in the Golgi apparatus by other glycosidase inhibitors had little effect on plant growth, although N-glycan processing was disrupted depending on inhibitor specificity. These results suggest that N-glycan processing after glucosidase processing is dispensable for plant growth and cell differentiation.
Asunto(s)
Retículo Endoplásmico/metabolismo , Glucosa/metabolismo , Polisacáridos/metabolismo , Raphanus/metabolismo , Plantones/metabolismo , 1-Desoxinojirimicina/farmacología , Amino Azúcares/farmacología , Cromatografía Líquida de Alta Presión/métodos , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/farmacología , Glucosa/análisis , Glicósido Hidrolasas/antagonistas & inhibidores , Glicósido Hidrolasas/metabolismo , Aparato de Golgi/metabolismo , Indolizinas/farmacología , Modelos Biológicos , Oligosacáridos/análisis , Oligosacáridos/metabolismo , Hojas de la Planta/efectos de los fármacos , Hojas de la Planta/crecimiento & desarrollo , Hojas de la Planta/metabolismo , Raphanus/química , Raphanus/crecimiento & desarrollo , Ramnosa/análogos & derivados , Ramnosa/farmacología , Plantones/efectos de los fármacos , Plantones/crecimiento & desarrollo , Swainsonina/farmacologíaRESUMEN
An attempt was made to convert the N-glycan structures in Raphanus sativus seeds during germination with a view to develop a method for regulating the N-glycan structures using glycosidase inhibitors. The N-glycan structures of glycoproteins in the roots of seedlings germinated for three days were analyzed by hydrazinolysis followed by N-acetylation, pyridylamination and HPLC. Pyridylaminated sugar chains obtained in the absence of the inhibitors had plant type structures consisting of Man(3)FucXylGlcNAc(2)(M3FX), Man(5-9)GlcNAc(2)(high-Man) and GlcNAc(1-2)Man(3)FucXylGlcNAc(2)(GnM3FX and Gn2M3FX). When germinated in the presence of a glucosidase inhibitor (castanospermine or deoxynojirimycin), the amount of glucosyl high-Man-type structure increased and plant growth was inhibited. When germinated in the presence of a mannosidase inhibitor (swainsonine or deoxymannojirimycin), the amount of the high-Man-type structure increased and that of M3FX was low, and the growth was normal. In the presence of 2-acetamido 1, 2 di-deoxynojirimycin, those of GnM3FX and Gn2M3FX increased and the growth was normal. These results show that the N-glycan processing in both the endoplasmic reticulum (ER) and Golgi apparatus can be controlled artificially using glycosidase inhibitors, and that the glucosidase inhibitors could be useful for the study of the function of N-glycans in plants.
Asunto(s)
Inhibidores Enzimáticos/farmacología , Glicoproteínas/química , Glicósido Hidrolasas/antagonistas & inhibidores , Raíces de Plantas/efectos de los fármacos , Raphanus/metabolismo , 1-Desoxinojirimicina/farmacología , Secuencia de Carbohidratos , Cromatografía Líquida de Alta Presión , Relación Dosis-Respuesta a Droga , Retículo Endoplásmico/metabolismo , Glicósido Hidrolasas/metabolismo , Indolizinas/farmacología , Modelos Biológicos , Datos de Secuencia Molecular , Oligosacáridos/química , Raíces de Plantas/metabolismo , Polisacáridos/química , Swainsonina/farmacología , Factores de TiempoRESUMEN
To develop a convenient method to isolate lectins, we prepared an affinity gel by coupling plasma proteins with agarose beads under conditions where the pH did not exceed 7.5. The validity of the use of this affinity gel in combination with elution using a hapten saccharide was confirmed by isolation of concanavalin A from Jack bean meal. Successful application of the method was demonstrated by isolation of two novel vegetable lectins from udo (Aralia cordate) and wasabi (Wasabia japonica). The method would be useful to isolate new lectins from various sources including plant and animal tissues.