Seawater Proteomics

尽管海洋中大量的碳以溶解有机物(DOM)的形式储存在海洋中，但由于这种非均质库的复杂性，人们在分子水平上对这种高相对分子质量的有机物知之甚少，这种缺乏阻碍了人们对控制其循环的机制的更详细的了解。来自西弗吉尼亚大学和波多黎各大学的科学家联手研究了DOM的一个重要组成部分--海洋中的溶解蛋白质。虽然只占DOM的一小部分，但蛋白质是溶解的有机氮库的主要组成部分，这些有机氮库产生于细胞裂解或排泄等过程。他们将利用蛋白质组学分析的巨大进步，使用最先进的质谱分析对海洋蛋白质进行排序和鉴定。完整的蛋白质将用傅里叶变换质谱仪进行分析，以了解凝胶电泳法分离的蛋白质条带的复杂性。因此，通过从头测序获得的多肽标签的可靠性和特异性将得到提高。直接数据库匹配和同源搜索应该会为溶解蛋白质的来源提供重要线索。将搜索这些数据，以寻找表明存在翻译后蛋白质修饰的证据。将确定已识别的修饰的特征，以确定它们是普通的生物修饰还是似乎是非生物过程的结果。成功地将这些技术转移到海洋将为解决有关有机氮的来源和变化的长期问题开辟道路，有机氮是海洋生物的重要氮库。在更广泛的影响方面，这项研究的结果将开始利用海洋生物迅速增长的基因组序列的知识，将迅速成熟的蛋白质组学技术应用于海洋有机氮的化学。作为这项研究的一部分，一名研究生和一名接受过化学海洋学培训的博士后将接受这些新技术的培训。

ABSTRACTOCE-0453737Although large amounts of carbon are stored in the oceans as dissolved organic matter (DOM), the complexity of this heterogeneous pool has meant that little is known about the high molecular weight organic matter at the molecular level, and this lack has hindered a more detailed understanding of the mechanisms that control its cycling. Scientists from the University of West Virginia and from the University of Puerto Rico have teamed up to study an important component of DOM, the dissolved proteins in the ocean. Although only a small fraction of the DOM, proteins are, however, a primary component of the dissolved organic nitrogen pool that arises from processes such as cell lysis or excretion. They will take advantage of the dramatic improvements in proteomic analysis to sequence and identify marine proteins using state-of-the-art mass spectrometric analysis. Intact proteins will be analyzed with Fourier transform mass spectrometry to access the complexity of protein bands separated by gel electrophoresis. The reliability and specificity of peptide tags obtained through de novo sequencing will hence be improved. Direct database matching and homology searching should yield important clues to the sources of dissolved proteins. The data will be searched for evidence suggesting the presence of post-translational protein modifications. Identified modifications will be characterized to determine if they are common biological modifications or if they appear to be the result of abiotic processes. Successful transfer of these techniques to the ocean will open the way for resolution of longstanding issues concerning the sources and changes in organic nitrogen, an important reservoir of nitrogen for marine life. In terms of broader impacts, results from this study will begin to apply the rapidly maturing technology of proteomics to the chemistry of organic nitrogen in the oceans, leveraging knowledge from the burgeoning genomic sequences of marine organisms. A graduate student, and a postdoctoral fellow with training in Chemical Oceanography, will be trained in these new techniques as part of this study.