Synthesis of Silica Forming Phosphoproteins

有机化学的有效制备方法是合成更长的长链多胺（LCPA）和高度修饰的磷酸肽如silaffin 1-A1的关键，其在15个氨基酸中的11个上具有翻译后修饰。为此，我们将扩大适用性的借用氢策略的合成LCPA和寡胺扩展赖氨酸。聚阳离子目标分子随后将与研究单位的其他小组合作，在仿生二氧化硅沉淀实验中进行研究。合成（LCPA）和聚阳离子肽配备有位点特异性标签是一个有价值的信息来源，在分析无定形二氧化硅。沿LCPA链沿着的不同碳和氮位置处的NMR同位素标记测量LCPA分子与沉淀二氧化硅的有机和无机组分之间的相边界处的最近硅原子之间的距离。然后将这些实验弛豫数据与来自建模实验的Si-N距离进行比较。NMR竞争实验能够对合成分子的二氧化硅沉淀性质进行排序。本项目的另一个目标是进一步发展我们的溶液NMR方法，用于跟踪多元化合物的二氧化硅沉淀实验。溶液核磁共振作为一种快速、定量和可靠的方法来跟踪二氧化硅沉淀过程。此外，NMR是能够区分凝胶化从二氧化硅沉淀，它将被用来在搜索假定的硅有机配合物，可能会发生之间的LCPA和原酸在溶液中的瞬态。

Efficient preparative methods of organic chemistry are key to synthesize longer long-chain polyamines (LCPA) and highly modified phosphopeptides like silaffin1-A1 which bears posttranslational modifications on 11 out of 15 amino acids. To this end we will expand the applicability of the Borrowing Hydrogen strategy for the synthesis of LCPA and oligoamine-extended Lysine. The polycationic target molecules will be studied subsequently in biomimetic silica precipitation experiments in collaboration with other groups of the Research Unit. Synthetic (LCPA) and polycationic peptides equipped with site-specific labels are a valuable source of information in the analysis of amorphous silica. The NMR isotope labels at different carbons and nitrogen positions along the LCPA chain measure the distance between the LCPA molecule and the closest silicon atom at the phase boundary between organic and inorganic components of the precipitated silica. These experimental relaxation data are then compared with Si-N distances from modeling experiments. NMR competition experiments are able to rank the silica precipitation properties of the synthetic molecules. The further development of our solution NMR methods for the tracking of silica precipitation experiments with the polybasic compounds are another objective of this project. Solution NMR as a fast, quantitative, and reliable method to follow the silica precipitation process. Furthermore, NMR is able to differentiate gelation from silica precipitation and it will be employed in the search of supposed Si-organic complexes which may occur transiently between LCPA and orthosilicic acid in solution.