CELL WALL POLYSACCHARIDE COMPOSITION AND COVALENT CROSSLINKING
CELL WALL POLYSACCHARIDE COMPOSITION AND COVALENT CROSSLINKING
复制标题
DOI：
10.1002/9781444391015.ch1
复制
发表时间：
2011-01-01
期刊：
影响因子：
--
通讯作者：
Fry, Stephen C.
中科院分区：
文献类型：
--
作者：
Fry, Stephen C.
遗传学现在有可能让我们改变细胞壁多糖的产生、交联和降解。然而，仍然需要通过实验测试多糖代谢的预期修饰是否已在体内成功地实现。简单的方法，这是描述，包括在体内放射性标记，酶解剖（如与Driselase）和层析/电泳分离的解剖products.After多糖化学的概述，我讨论的结构和分类分布壁多糖轮藻和陆地植物。主要的壁多糖是纤维素[微纤维β-（1 -> 4）-d-葡聚糖]、果胶（富含α-D-半乳糖醛酸）和半纤维素（缺乏半乳糖醛酸;与纤维素氢键合;在37 ℃下可通过6 M NaOH提取）。陆生植物果胶是由约四个糖苷相互连接的结构域（同型半乳糖醛酸聚糖、鼠李半乳糖醛酸聚糖I和II、木半乳糖醛酸聚糖）构建的阴离子聚合物。存在于大多数/所有陆地植物中的半纤维素是α-木-β-葡聚糖、β-木聚糖（包括α-阿拉伯-β-木聚糖、α-葡糖醛酸-β-木聚糖等）。和β-甘露聚糖（包括α-半乳糖-β-甘露聚糖、β-葡糖-β-甘露聚糖等）。另一种半纤维素[混合键β-（1 -> 3）（1 -> 4）-D-葡聚糖]仅限于木贼属和一些禾本科植物。被子植物初生壁的其他分类学限制特征出现在禾本科植物（木糖贫乏的木葡聚糖;阿魏酰化阿拉伯聚糖）;茄目和唇形科植物（特征性木葡聚糖）;角叉菜目（阿魏酰化果胶）;和泽泻目（apiogalacturonan）。我还总结了轮藻、苔藓植物、石松植物、蕨类植物和裸子植物的细胞壁特征。“交联”（定义为单个化学键，而不是整个“拴系”链）的形成或断裂可能导致细胞壁收紧/松弛。共价交联包括酚偶联产物、糖醛酸酯和酰胺以及硼酸二酯。
Genetics now potentially lets us modify the production, crosslinking and degradation of cell wall polysaccharides. There remains, however, the need to test experimentally whether intended modifications of polysaccharide metabolism have successfully been effected in vivo. Simple methods for this are described, including in-vivo radiolabelling, enzymic dissection (e.g. with Driselase) and chromatographic/electrophoretic fractionation of dissection products.After an overview of polysaccharide chemistry, I discuss the structures and taxonomic distribution of wall polysaccharides in charophytes and land plants. Primary and secondary walls are compared.The major wall polysaccharides are cellulose [microfibrillar beta-(1 -> 4)-d-glucan], pectins (alpha-D-galacturonate-rich) and hemicelluloses (lacking galacturonate; hydrogen-bonding to cellulose; extractable by 6 M NaOH at 37 degrees C). Land-plant pectins are anionic polymers built of about four glycosidically interconnected domains (homogalacturonan, rhamnogalacturonans I and II, xylogalacturonan). Hemicelluloses occurring in most/all land plants are alpha-xylo-beta-glucans, beta-xylans (including alpha-arabino-beta-xylans, alpha-glucurono-beta-xylans, etc.) and beta-mannans (including alpha-galacto-beta-mannans, beta-gluco-beta-mannans, etc.). Another hemicellulose [mixed-linkage beta-(1 -> 3)(1 -> 4)-D-glucan) is confined to Equisetum and some Poales.Other taxonomically restricted features of angiosperm primary walls occur in Poales (xylose-poor xyloglucans; feruloylated arabinoxylans); Solanales and Lamiales (characteristic xyloglucans); Caryophyllales (feruloylated pectins); and Alismatales (apiogalacturonan). I also summarize characteristic wall features of charophytes, bryophytes, lycopodiophytes, fern-allies and gymnosperms.The making or breaking of a 'crosslink' (defined as an individual chemical bond, not a whole 'tethering' chain) may cause wall tightening/loosening. Covalent crosslinks include phenolic coupling products, uronoyl esters and amides, and borate diesters.