Beyond the Mineral Sorptive Protection Hypothesis: Protein Preservation in Marine Systems via Formation of High-Molecular Mass Aggregates

摘要本研究的重点是更好地了解海洋沉积物和水柱中高分子量（~ 106 D）富氮大分子蛋白质物质的保存机制。其中一些分子存在于数千年前的沉积物中。蛋白质作为富含能量的生化底物，通常在环境中被一系列高亲和力的细菌蛋白酶和酶系统迅速降解，因此蛋白质类大分子在底物(N)缺乏的沉积物中长时间的持久性仍然没有得到充分的解释。通过在难以接近的沉积物介孔中选择性吸附保护、结构修饰（如糖基化、缩合或络合）、在生物化学抗性材料（如膜或细胞壁成分）中聚集和包封来保存是一些建议的机制。可能所有这些都在某种程度上起作用。本研究旨在研究多肽在矿物表面上的非共价相互作用范围，或将代表性蛋白质包封到折射生物聚合物中，作为导致这些分子保存的潜在重要控制因素。一系列的实验室操作实验和蛋白质表征技术，使用广泛的分析工具，并应用于沉积和颗粒相关的有机物，将用于检验这些保存机制的支持。浅海和深海中碳化合物的周转率对我们了解海洋碳循环非常重要。

ABSTRACTOCE-0136631The focus of this research is a better understanding the mechanisms of the preservation of high molecular weight (~ 106 D) nitrogen rich macromolecular proteinaceous material in marine sediments and in the water column. Some of these molecules persist in sediments that are thousands of years old. Proteins, as energy rich biochemical substrates, are normally rapidly degraded in the environment by a range of high affinity bacterial proteases and enzyme systems, so the persistence of protein-like macromolecules for long periods of time in substrate (N) poor sediments remains inadequately explained. Preservation through selective sorptive protection in inaccessible sediment mesopores, structural modification such as glucosylation, condensation or complexation, aggregation and encapsulation in biochemically resistant materials such as membrane or cell wall components are some of the suggested mechanisms. Possibly all of these may operate to some extent. This study sets out to investigate range of non-covalent interactions entered into by polypeptides on mineral surfaces and or encapsulation of representative proteins into refractive biopolymers as potential important controlling factors resulting in preservation of such molecules. A series of laboratory manipulation experiments and protein characterization techniques, using a wide range of analytical tools, and applied to sedimentary and particulate associated organic matter will be used to examine support for these preservation mechanisms. The rates of turnover of carbon compounds in the shallow and deep seas is of importance to our understanding of the ocean's carbon cycle.