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Characterization of the metal binding site of rhamnogalacturonan II from plant cell walls

植物细胞壁鼠李半乳糖醛酸 II 金属结合位点的表征

基本信息

批准号：
15580053
负责人：
MATSUNAGA Toshiro
金额：
$ 0.9万
依托单位：
National Agriculture and Bio-oriented Research Organization
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15580053/
关键词：
rhamnogalacturonan II lanthanoid size-exclusion HPLC ICP-MS plant cell-wall polysaccharide boron

项目摘要

Rhamnogalacturonan II (RG-II) is a structurally complex pectic polysaccharide isolated from vascular plant cell walls, and is composed of a backbone of galacturonic acid (GalA) residues and four side chains of diverse glycosyl residues. Recently, a dimeric RG-II - borate complex (dRG-II-B) in which a borate-diol ester (1:2) cross-links two monomeric RG-II (mRG-II) was isolated from pectinase digests of plant cell walls. It has been shown that RG-II is covalently linked to homogalacturonan, a major component of pectin in plant cell walls, and that dRG-II-B formation contributes to stabilization of the cell walls. These studies have demonstrated that the primary function of boron, an essential microelement for plants, is to covalently cross-link wall pectin by dRG-II-B formation, and thereby to contribute to the strength and integrity of the cell walls. The dRG-II-B complex contains specific metals, such as Ca, Sr, Ba, and Pb. However, the function of metal ions bound to dRG-II-B has not … More been established. In the present study, the metal contents of RG-II and its partial hydrolysates that were treated with metal ions were determined by size-exclusion high-performance liquid chromatography / inductively coupled plasma mass spectrometry (SE-HPLC/ICP-MS) to understand the RG-II's affinity and binding site for metals.The partially hydrolyzed mRG-II (sugar beet and red wine) was treated with La^<3+>, and then analyzed by SE-HPLC/RI and SE-HPLC/ICP-MS to determine the contribution of each side chain of mRG-II to form a lanthanoid binding site. The amount and molecular weight of the mRG-II major peak gradually decreased with intensification of the hydrolysis treatment, which accompanied a decrease in the amount of La bound to the major peak. In the lower molecular weight region, no mRG-II fragment complexed with La was observed. These results indicate that the La binding site in mRG-II can be attributed not to a single glycosyl residue and side chain, but to an assembly of side chains and a GalA backbone. Less

鼠李半乳糖醛酸聚糖II（RG-II）是从维管植物细胞壁中分离的结构复杂的果胶多糖，并且由半乳糖醛酸（GalA）残基的主链和四个不同糖基残基的侧链组成。最近，从植物细胞壁的果胶酶底物中分离出二聚体RG-II -硼酸盐复合物（dRG-II-B），其中硼酸酯-二醇酯（1：2）交联两个单体RG-II（mRG-II）。已经表明，RG-II与植物细胞壁中果胶的主要组分同型半乳糖醛酸共价连接，并且dRG-II-B的形成有助于细胞壁的稳定。这些研究已经证明，硼（植物必需的微量元素）的主要功能是通过dRG-II-B形成共价交联壁果胶，从而有助于细胞壁的强度和完整性。dRG-II-B络合物含有特定的金属，例如Ca、Sr、Ba和Pb。然而，与dRG-II-B结合的金属离子的功能尚未被证实。 ...更多信息确立了习本研究采用体积排阻高效液相色谱/电感耦合等离子体质谱法（Size-exclusionHPLC-MS/ICP-MS）测定了RG-II及其经金属离子处理后的部分水解产物中的金属含量通过SE-HPLC/ICP-MS分析来了解RG-II对金属的亲和力和结合位点。（甜菜和红葡萄酒），然后通过SE-HPLC/RI和SE-HPLC/ICP-MS分析以确定mRG-II的每个侧链对形成镧系元素结合位点的贡献。随着水解处理的加强，mRG-II主峰的量和分子量逐渐降低，这伴随着与主峰结合的La的量的降低。在较低分子量区域，未观察到与La复合的mRG-II片段。这些结果表明，在mRG-II的La结合位点可以归因于不是一个单一的糖基残基和侧链，但组装的侧链和GalA骨架。少