Soto Maria J, Prabhakar Pradeep Kumar, Wang Hsin-Tzu, Backe Jason, Chapla Digantkumar, Bartetzko Max, Black Ian M, Azadi Parastoo, Peña Maria J, Pfrengle Fabian, Moremen Kelley W, Urbanowicz Breeanna R, Hahn Michael G
Lawrence Berkeley National Laboratory, DOE Joint Genome Institute, Berkeley, CA, United States.
The Complex Carbohydrate Research Center, University of Georgia, Athens, GA, United States.
Front Plant Sci. 2021 Feb 9;12:589518. doi: 10.3389/fpls.2021.589518. eCollection 2021.
The bulk of plant biomass is comprised of plant cell walls, which are complex polymeric networks, composed of diverse polysaccharides, proteins, polyphenolics, and hydroxyproline-rich glycoproteins (HRGPs). Glycosyltransferases (GTs) work together to synthesize the saccharide components of the plant cell wall. The fucosyltransferases (FUTs), FUT4, and FUT6, are members of the plant-specific GT family 37 (GT37). FUT4 and FUT6 transfer fucose (Fuc) onto arabinose (Ara) residues of arabinogalactan (AG) proteins (AGPs) and have been postulated to be non-redundant AGP-specific FUTs. FUT4 and FUT6 were recombinantly expressed in mammalian HEK293 cells and purified for biochemical analysis. We report an updated understanding on the specificities of FUT4 and FUT6 that are involved in the synthesis of wall localized AGPs. Our findings suggest that they are selective enzymes that can utilize various arabinogalactan (AG)-like and non-AG-like oligosaccharide acceptors, and only require a free, terminal arabinofuranose. We also report with GUS promoter-reporter gene studies that and gene expression is sub-localized in different parts of developing roots.
植物生物量的大部分由植物细胞壁组成，植物细胞壁是复杂的聚合物网络，由多种多糖、蛋白质、多酚和富含羟脯氨酸的糖蛋白（HRGPs）组成。糖基转移酶（GTs）共同作用以合成植物细胞壁的糖类成分。岩藻糖基转移酶（FUTs），即FUT4和FUT6，是植物特有的GT37家族成员。FUT4和FUT6将岩藻糖（Fuc）转移到阿拉伯半乳聚糖（AG）蛋白（AGPs）的阿拉伯糖（Ara）残基上，并且被认为是无冗余的AGP特异性FUTs。FUT4和FUT6在哺乳动物HEK293细胞中重组表达并纯化以进行生化分析。我们报告了对参与壁定位AGPs合成的FUT4和FUT6特异性的最新认识。我们的研究结果表明，它们是选择性酶，能够利用各种阿拉伯半乳聚糖（AG）样和非AG样寡糖受体，并且只需要一个游离的、末端阿拉伯呋喃糖。我们还通过GUS启动子报告基因研究报告了 和 基因表达在发育中的根的不同部位亚定位。
