SGER: Synthetic Genes for the Design of Hydroxproline-Rich Glycomodules

小行星9805960 富含羟脯氨酸的糖蛋白（HRGP）是生长中植物细胞壁的普遍存在的结构成分，通常占其干重的10-20%;多糖占大部分。 HRGPs参与植物生长和发育的各个方面，包括对胁迫的反应。 HRGP超家族包含代表糖基化和周期性连续体的三个主要基团。 它们的范围从轻度糖基化和高度周期性的重复富含脯氨酸的蛋白质，通过高度阿拉伯糖基化和周期性的交联延伸蛋白，到最高度糖基化和最少周期性的阿拉伯半乳聚糖蛋白质。 重复单元很小，通常只有4-6个残基的糖基化基序，被假设为功能模块。 这些独特的植物糖蛋白的功能仍然在很大程度上未被探索。 我们建议通过功能分析的单一糖肽模块时，表达为重复glycopolypeptides在番茄培养物中的作用。 我们将编码HRGP糖肽模块的合成基因插入两个植物转化载体中，这两个载体都来自pBI 121;一个具有报告基因，另一个用于测试模块功能，缺少报告基因。 我们将使用这些质粒转化番茄的细胞培养物，其中含有模块翻译后修饰所需的植物脯氨酰羟化酶和糖基转移酶。 这些模块的表达和分离将使我们能够测试糖基化和分子功能的一般和特定假设：1。由Hyp-contiguity假说预测的糖基化代码指定了对特定HRGP Hyp残基的精确糖添加，即：四阿拉伯糖添加到最高度连续的残基，阿拉伯糖基化随着Hyp-contiguity的降低而降低;以及代表AGP的重复非连续Hyp残基的多聚半乳糖基化。 2.碳水化合物介导的伸展蛋白单体的排列对于它们在细胞壁自组装中的有序组装和交联作用是必要的。

9805960 Kieliszewski Hydroxyproline-rich glycoproteins (HRGPs) are ubiquitous architectural components of growing plant cell walls, often accounting for 10-20% of their dry weight; polysaccharides account for the bulk. HRGPs are implicated in all aspects of plant growth and development including responses to stress. The HRGP superfamily contains three major groups representing a continuum of glycosylation and periodicity. They range from the repetitive proline-rich proteins that are lightly glycosylated and highly periodic, through the crosslinked extensins that are highly arabinosylated and periodic, to the arabinogalactan-proteins that are the most highly glycosylated and least periodic. The repetitive units are small, often only 4-6 residue glycosylated motifs viewed hypothetically as functional modules. The function of these unique plant glycoproteins remains largely unexplored. We propose to define their roles through functional analysis of single glycopeptide modules when expresssed as repetitive glycopolypeptides in tomato cultures. We shall insert synthetic genes encoding HRGP glycopeptide modules into two plant transformation vectors both derived from pBI121; one with a reporter gene, the other, for test for module function, lacking the reporter. We shall use these plasmids to transform cell cultures of tomato, which contain the plant prolylhydroxylases and glycosyltransferases required for module posttranslational modifications. Expression and isolation of these modules will enable us to test general and specific hypotheses for glycosylation and molecular function: 1. Glycosylation codes predicted by the Hyp-contiguity hypothesis specify precise saccharide addition to specific HRGP Hyp residues, namely: tetraarabinose to the most highly contiguous residues, arabinosylation decreasing with decreasing Hyp-contiguity; and polygalactosylation of repetitive noncontiguous Hyp residues that typify AGPs. 2. Carbohydrate-mediated alignment of extensin monomers is necessary for their orderly assembly and crosslinking roles in cell wall self-assembly.