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End date: 2019Subject: search.filters.subject.glycosylation

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    LIMITED ADDITION OF THE 6-ARM Β1,2-LINKED N-ACETYLGLUCOSAMINE (GLCNAC) RESIDUE FACILITATES THE FORMATION OF THE LARGEST N-GLYCAN IN PLANTS
    (Pub Med, 2015-07-03) Jae, Yong Yoo; Ki, Seong Ko; Hyun-Kyeong, Seo; Seongha, Park; Wahyu, Indra Duwi Fanata; Rikno, Harmoko; Nirmal Kumar, Ramasamy; Thiyagarajan, Thulasinathan; Tesfaye, Mengiste; Jae-Min, Lim; Sang, Yeol Lee; Kyun, Oh Lee
    The most abundant N-glycan in plants is the paucimannosidic N-glycan with core β1,2-xylose and α1,3-fucose residues (Man3XylFuc(GlcNAc)2). Here, we report a mechanism in Arabidopsis thaliana that efficiently produces the largest N-glycan in plants. Genetic and biochemical evidence indicates that the addition of the 6-arm β1,2-GlcNAc residue by N-acetylglucosaminyltransferase II (GnTII) is less effective than additions of the core β1,2-xylose and α1,3-fucose residues by XylT, FucTA, and FucTB in Arabidopsis. Furthermore, analysis of gnt2 mutant and 35S:GnTII transgenic plants shows that the addition of the 6-arm non-reducing GlcNAc residue to the common N-glycan acceptor GlcNAcMan3(GlcNAc)2 inhibits additions of the core β1,2-xylose and α1,3-fucose residues. Our findings indicate that plants limit the rate of the addition of the 6-arm GlcNAc residue to the common N-glycan acceptor as a mechanism to facilitate formation of the prevalent N-glycans with Man3XylFuc(GlcNAc)2 and (GlcNAc)2Man3XylFuc(GlcNAc)2 structures.
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    N-GLYCAN CONTAINING A CORE Α1,3-FUCOSE RESIDUE IS REQUIRED FOR BASIPETAL AUXIN TRANSPORT AND GRAVITROPIC RESPONSE IN RICE (ORYZA SATIVA)
    (2016-05-31) Rikno, Harmoko; Jae Yong, Yoo; Ki Seong, Ko; Nirmal Kumar, Ramasamy; Bo Young, Hwang; Eun, Ji Lee; Ho Soo, Kim; Kyung, Jin Lee; Doo-Byoung, Oh; Dool, -Yi Kim; Sanghun, Lee; Yang, Li; Sang Yeol, Lee; Kyun, Oh Lee
    In plants, α1,3-fucosyltransferase (FucT) catalyzes the transfer of fucose from GDP-fucose to asparagine-linked GlcNAc of the N-glycan core in the medial Golgi. To explore the physiological significance of this processing, we isolated two Oryza sativa (rice) mutants (fuct-1 and fuct-2) with loss of FucT function. Biochemical analyses of the N-glycan structure confirmed that α1,3-fucose is missing from the N-glycans of allelic fuct-1 and fuct-2. Compared with the wild-type cv Kitaake, fuct-1 displayed a larger tiller angle, shorter internode and panicle lengths, and decreased grain filling as well as an increase in chalky grains with abnormal shape. The mutant allele fuct-2 gave rise to similar developmental abnormalities, although they were milder than those of fuct-1. Restoration of a normal tiller angle in fuct-1 by complementation demonstrated that the phenotype is caused by the loss of FucT function. Both fuct-1 and fuct-2 plants exhibited reduced gravitropic responses. Expression of the genes involved in tiller and leaf angle control was also affected in the mutants. We demonstrate that reduced basipetal auxin transport and low auxin accumulation at the base of the shoot in fuct-1 account for both the reduced gravitropic response and the increased tiller angle.