Synthetic and structural studies on hydroxyproline-rich glycopeptides

富含羟脯氨酸糖肽的合成和结构研究

• 批准号: 261311-2008
• 负责人: Schweizer, Frank
• 金额: $ 3.06万
• 依托单位: University of Manitoba
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2009
• 资助国家: 加拿大
• 起止时间: 2009-01-01 至 2010-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=426543
• 关键词: Synthetic; structural; studies; hydroxyproline; rich

Proline is unique among the proteinogenic amino acids as its side chain is fused to the peptide backbone. As a consequence, there is a reduction in the energy difference between the prolyl amide cis and trans isomers, making them nearly isoenergetic; this leads to a higher cis N-terminal amide population relative to other amino acids. Moreover, the isomerization of the prolyl amide bond has been shown to be the rate-determining step in the folding pathway of many peptides and proteins. Besides exhibiting unique conformational properties and inducing important secondary structures (beta-turns and polyproline helix) proline also undergoes post-translational modifications such as hydroxylation followed sometimes by glycosylation. Glycosylation of hydroxyproline (Hyp) is widespread in the plant kingdom and occurs in Hyp-rich glycoprotein/peptides (HRGPs) that are associated with the cell walls of algae and flowering plants. However, the structural, conformational and biological implications of Hyp-glycosylation have not been addressed. This discovery grant explores the structure-function relationships of glycosylated Hyp-peptides in model peptides. In the short-term we will develop synthetic methodologies to prepare suitably protected glycosyl hydroxyproline building blocks that will be incorporated into peptides by solid-phase synthesis. In the longer-term, we will probe the structural, conformational, kinetic and physical properties of Hyp-glycosylation in plant-derived HRGPs as well as artificial Hyp-glycosylation of human-derived Hyp-rich peptides by nuclear magnetic resonance, circular dichroism and differential scanning calorimetry. The outcome of our research will provide for the first time insight into the structural, conformational, physical and biological implications of post-translational Hyp glycosylation in proteins and peptides and will impact many diverse research areas ranging from structural (glyco)biology to materials science.

脯氨酸在蛋白质氨基酸中是独特的，因为其侧链与肽骨架融合。因此，脯氨酰酰胺顺式和反式异构体之间的能量差减少，使它们几乎等能;这导致相对于其他氨基酸的更高的顺式N-末端酰胺群体。此外，脯氨酰酰胺键的异构化已被证明是许多肽和蛋白质折叠途径中的速率决定步骤。除了表现出独特的构象特性和诱导重要的二级结构（β-转角和聚脯氨酸螺旋）外，脯氨酸还经历翻译后修饰，例如羟基化，随后有时是糖基化。羟脯氨酸（Hyp）的糖基化广泛存在于植物界，并且发生在与藻类和开花植物的细胞壁相关的富含Hyp的糖蛋白/肽（HRGP）中。然而，结构，构象和生物学意义的高糖基化尚未解决。这项发现资助探索了模型肽中糖基化Hyp-peptides的结构-功能关系。在短期内，我们将开发合成方法来制备适当保护的糖基羟脯氨酸构建块，将纳入肽固相合成。从长远来看，我们将通过核磁共振、圆二色性和差示扫描量热法来探索植物源HRGPs中Hyp-glycosylation的结构、构象、动力学和物理性质，以及人源Hyp-rich肽的人工Hyp-glycosylation。 我们的研究成果将首次深入了解蛋白质和肽中翻译后Hyp糖基化的结构，构象，物理和生物学意义，并将影响从结构（糖）生物学到材料科学的许多不同的研究领域。