Cysteine Reactivity as a Probe of the Proteome

Abstract

The study of protein folding and stability is typically conducted with purified proteins by methods that are exacting but lack the ability to analyze complex mixtures of proteins. To study proteins in their native environments inside a cell or isolated organelle, such as a nucleus, we have recently developed a powerful method that combines shotgun labelling with LC/MS/MS. Cysteine is a reactive but hydrophobic amino acid that can be fluorescently labelled in isolated nuclei with time resolution under stress conditions (changes in temperature). Quantitative kinetic analyses of spectra allow us to identify regions in hundreds of proteins, including nuclear lamins implicated in diseases such as Progeria, to understand the folding and interactions in situ. Select protein domains are also studied in solution, demonstrating the close correspondence to more traditional methods.View Large Image | View Hi-Res Image | Download PowerPoint Slide