The chemistry of metals is rich and viewed in a biological context its diversity is crucial for a multitude of molecular functions in the living cell. In this proposal, I plan to develop novel applications of metal compounds to solve immediate challenges in mass spectrometry-based proteome research, and also assess the potential risks of using nano-sized metals in our society. Presently, C-terminal peptide amidation poses a challenge in pharmaceutical production due to limitations of the two enzymes used for this purpose. The suggested approach in METALS will examine if C-terminal amidated peptides can be produced by specific binding of uranyl to phosphorylated peptides with subsequent UV irradiation of the complex. Attempt will be made to minimize the bias inherent in current phosphopeptide analysis. Application of a recently developed digallium complex with high affinity to protein phosphorylations can potentially advance this line of research. Finally, humans are now exposed to increasing amounts of artificially nano-metals applied via consumer products, food packages, and cosmetics. I will investigate nano-bio interactions using advanced mass spectrometry, confocal microscopy, and biochemical assays to assess the responses in human neural cells to nano-metal particles.
The Main conclusions that can be drawn from the METALS program are:
1) The invented digallium complex is a valuable chemical for phosphoproteomics studies as it can limit the extent of miscleavages by trypsin during digestion of phosphoproteins, 2) formation of C-terminally amidated peptides is possible by application of photo-induced dissociation of uranyl-bound phosphopeptides, but a limitation exists in the lack of specificity of bond breakage. 3) Proteomics studies of cells and animals exposed to various nanoparticles reveal unprecedented details of cellular mechanistic for toxicity that can assist future legislation, but also propel new strategies for cancer treatment.
