MYELIN PO GLYCOPROTEIN: STRUCTURE & ADHESIVE MECHANISMS

髓磷脂 PO 糖蛋白：结构

• 批准号: 6052823
• 负责人: DANIEL A KIRSCHNER
• 金额: $ 22.86万
• 依托单位: BOSTON COLLEGE
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-01-15 至 2003-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6052823
• 关键词: X ray crystallography; Xenopus; animal tissue; cell cell interaction; glycoprotein structure; low angle X ray diffraction analysis; membrane structure; molecular assembly /self assembly; myelin; myelin glycoprotein; protein protein interaction; protein structure function; recombinant proteins

DESCRIPTION (Applicant's abstract): The overall objective of this application is to define the molecular organization of myelin, the diverse adhesive mechanisms that stabilize its multilamellar sheath, and what defects in its organization and molecular constituents may lead to dysmyelination or demyelination such as occur in certain peripheral neuropathies and in multiple sclerosis. The approach is based on a correlation of results from X-ray crystallography and solution scattering, membrane diffraction, and electron microscopy. The specific aims, which are focused on the structure and role of the major transmembrane protein of peripheral nerve myelin (P0-glycoprotein) are: (1) to determine the three-dimensional structure of P0-glycoprotein for human and Xenopus. The proteins analyzed will include recombinant molecules having the native amino acid sequence, as well as those having specific sequence alterations known to occur in human peripheral neuropathies. These studies will inform about the atomic structure of P0 and about the crystal contacts or adhesion interfaces that may be responsible for the role of this protein in myelin formation and stability. (2) To characterize the protein-protein interactions between nearest-neighbor P0 molecules in a membrane mimetic environment using small-angle X-ray scattering. The membrane protein will be solubilized in aqueous solutions of detergents at very low concentration, and solution scattering will be undertaken using a synchrotron X-ray source. These studies will provide information about the interprotein molecular contacts that P0 molecules make in a milieu that more closely resembles its native environment (the lipid bilayer of the myelin membrane) than does a crystal. (3) To evaluate the membrane-membrane interactions in myelin of Xenopus peripheral nerves. Determining the pH- and ionic strength-dependence of membrane structure and packing in dissected peripheral nerves that have been incubated at different will provide strong constraints for testing hypotheses about the adhesion mechanisms of P0 at both the cytoplasmic and extracellular membrane appositions. This hierarchy of experimental objectives will allow the investigator to uniquely correlate structural data from the atomic to the molecular, to the membrane level, and thus contribute to an understanding of the structural biology of a membrane protein that figures significantly in both health and disease.

描述（申请人的摘要）：总体目标 该应用程序是为了定义髓磷脂的分子组织，多样化 稳定其多层鞘的粘合机制以及哪些缺陷 其组织和分子成分可能导致髓鞘形成障碍或 脱髓鞘，例如发生在某些周围神经病和多种疾病中 硬化。该方法基于 X 射线结果的相关性 晶体学和溶液散射、膜衍射和电子 显微镜。具体目标，重点是结构和作用 周围神经髓磷脂的主要跨膜蛋白（P0-糖蛋白） (1)确定P0-糖蛋白的三维结构 人类和爪蟾。分析的蛋白质将包括重组分子 具有天然氨基酸序列，以及具有特定氨基酸序列的 已知发生在人类周围神经病中的序列改变。这些 研究将揭示 P0 的原子结构和晶体 可能负责此作用的接触或粘合界面 蛋白质参与髓磷脂的形成和稳定性。 (2) 表征 最近邻 P0 分子之间的蛋白质-蛋白质相互作用 使用小角度 X 射线散射的膜模拟环境。膜 蛋白质在极低的温度下会溶解在洗涤剂的水溶液中 浓度和溶液散射将使用同步加速器进行 X 射线源。这些研究将提供有关蛋白间蛋白的信息 P0 分子在更紧密的环境中进行分子接触 类似于其原生环境（髓磷脂膜的脂质双层） 比水晶更重要。 (3) 评价膜-膜相互作用 爪蟾周围神经的髓磷脂。测定 pH 值和离子 解剖外周膜结构和堆积的强度依赖性 不同培养的神经会提供很强的约束 用于测试有关 P0 的粘附机制的假设 细胞质和细胞外膜的并置。这个层次结构 实验目标将使研究者能够独特地关联 从原子到分子、到膜水平的结构数据，以及 从而有助于理解膜的结构生物学 对健康和疾病都具有重要意义的蛋白质。