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Structure of ten free N-glycans in ripening tomato fruit

The concentration-dependent stimulatory and inhibitory effect of N-glycans on tomato (Lycopersicon esculentum Mill.) fruit ripening was recently reported (B. Priem and K.C. Gross [1992] Plant Physiol 98: 399-401). We report here the structure of 10 free N-glycans in mature green tomatoes. N-glycans...

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Bibliographic Details
Published in:Plant physiology (Bethesda) 1993-06, Vol.102 (2), p.445-458
Main Authors: Priem, B, Gitti, R, Bush, C.A, Gross, K.C
Format: Article
Language:English
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Summary:The concentration-dependent stimulatory and inhibitory effect of N-glycans on tomato (Lycopersicon esculentum Mill.) fruit ripening was recently reported (B. Priem and K.C. Gross [1992] Plant Physiol 98: 399-401). We report here the structure of 10 free N-glycans in mature green tomatoes. N-glycans were purified from fruit pericarp by ethanolic extraction, desalting, concanavalin A-sepharose chromatography, and amine-bonded silica high performance liquid chromatography. N-glycan structures were determined using 500 MHz 1H-nuclear magnetic resonance spectroscopy, fast atom bombardment mass spectrometry, and glycosyl linkage methylation analysis by gas chromatography-mass spectrometry. A novel arabinosyl-containing N-glycan, Man alpha 1 leads to 6(Ara alpha 1 leads to 2)Man beta 1 leads to 4 GlcNAc beta 1 leads to 4(Fuc alpha 1 leads to 3)GlcNAc, was purified from a retarded concanavalin A fraction. The location of the arabinosyl residue was the same as the xylosyl residue in complex N-glycans. GlcNAc[5']Man3(Xyl)GlcNAc(Fuc)GlcNAc and GlcNAc[5']Man2GlcNAc(Fuc)GlcNAc were also purified from the weakly retained fraction. The oligomannosyl N-glycans Man5GlcNAc, Man6GlcNAc, Man7GlcNAc, and Man8GlcNAc were purified from a strongly retained concanavalin A fraction. The finding of free Man5GlcNAc in situ was important physiologically because previously we had described it as a promoter of tomato ripening when added exogenously. Mature green pericarp tissue contained more than 1 micrograms of total free N-glycan/g fresh weight. Changes in N-glycan composition were determined during ripening by comparing glycosyl and glycosyl-linkage composition of oligosaccharidic extracts from fruit at different developmental stages. N-glycans were present in pericarp tissue at all stages of development. However, the amount increased during ripening, as did the relative amount of xylosyl-containing N-glycans
ISSN:0032-0889
1532-2548
DOI:10.1104/pp.102.2.445