Synthesis of Silica Forming Phosphoproteins

高效的有机化学制备方法是合成长链多胺（LCPA）和高修饰磷酸肽（如silaffin1-A1）的关键，silaffin1-A1在15个氨基酸中有11个经过翻译后修饰。为此，我们将扩大借用氢策略在LCPA和低聚胺延伸赖氨酸合成中的适用性。随后将与研究股的其他小组合作，在仿生二氧化硅沉淀实验中研究多阳离子靶分子。合成（LCPA）和多阳离子肽配备的位置特异性标签是一个宝贵的信息来源，在分析无定形二氧化硅。LCPA链上不同碳和氮位置的核磁共振同位素标记测量了LCPA分子与沉淀二氧化硅有机和无机组分之间相界上最近的硅原子之间的距离。然后将这些实验松弛数据与模拟实验的Si-N距离进行比较。核磁共振竞争实验能够对合成分子的二氧化硅沉淀性能进行排序。该项目的另一个目标是进一步发展我们的溶液核磁共振方法，以跟踪多碱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、可靠的方法来跟踪二氧化硅沉淀过程。此外，核磁共振能够区分凝胶和二氧化硅沉淀，它将被用于寻找可能在溶液中LCPA和正硅酸之间短暂发生的硅有机配合物。

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.