Three members of the Arabidopsis glycosyltransferase family 8 are xylan glucuronosyltransferases
| Autor: | Masood Z. Hadi, Jay D. Keasling, Henrik Vibe Scheller, Sara Fasmer Hansen, Edward E. K. Baidoo, Emilie A. Rennie |
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| Rok vydání: | 2012 |
| Předmět: |
Models
Molecular Physiology Arabidopsis Biochemical Processes and Macromolecular Structures Plant Science macromolecular substances Xylose Cell wall chemistry.chemical_compound Glucuronoxylan Microsomes Glycosyltransferase Tobacco Genetics Arabidopsis thaliana Glucuronosyltransferase Phylogeny chemistry.chemical_classification biology Arabidopsis Proteins food and beverages Glycosyltransferases biology.organism_classification Xylan Recombinant Proteins carbohydrates (lipids) Protein Transport Biochemistry chemistry biology.protein Xylans Secondary cell wall Subcellular Fractions |
| Zdroj: | Plant physiology. 159(4) |
| ISSN: | 1532-2548 |
| Popis: | Xylan is a major component of the plant cell wall and the most abundant noncellulosic component in the secondary cell walls that constitute the largest part of plant biomass. Dicot glucuronoxylan consists of a linear backbone of β(1,4)-linked xylose residues substituted with α(1,2)-linked glucuronic acid (GlcA). Although several genes have been implicated in xylan synthesis through mutant analyses, the biochemical mechanisms responsible for synthesizing xylan are largely unknown. Here, we show evidence for biochemical activity of GUX1 (for GlcA substitution of xylan 1), a member of Glycosyltransferase Family 8 in Arabidopsis (Arabidopsis thaliana) that is responsible for adding the glucuronosyl substitutions onto the xylan backbone. GUX1 has characteristics typical of Golgi-localized glycosyltransferases and a K m for UDP-GlcA of 165 μm. GUX1 strongly favors xylohexaose as an acceptor over shorter xylooligosaccharides, and with xylohexaose as an acceptor, GlcA is almost exclusively added to the fifth xylose residue from the nonreducing end. We also show that several related proteins, GUX2 to GUX5 and Plant Glycogenin-like Starch Initiation Protein6, are Golgi localized and that only two of these proteins, GUX2 and GUX4, have activity as xylan α-glucuronosyltransferases. |
| Databáze: | OpenAIRE |
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