Search

Coimmunoprecipitation is a powerful and commonly used method to identify protein-protein interactions in a physiological context. Here, we report a coimmunoprecipitation protocol that was adapted and optimized for the haloarchaeon Haloferax volcanii to identify interacting partners to the LonB protease. This protocol includes the in vivo cross-linking of H. volcanii proteins using two different crosslinker agents, dithiobis(succinimidyl propionate) and formaldehyde, followed by immunoprecipitation with anti-LonB antibody conjugated to Protein A - Sepharose beads. Tryptic on-bead protein digestion was performed combined with Mass Spectrometry analysis of peptides for the identification and quantification of LonB ligands.

The cellular protein repertoire is highly dynamic and responsive to internal or external stimuli. Its changes are largely the consequence of the combination of protein synthesis and degradation, referred collectively as protein turnover. Different proteomics techniques have been developed to determine the whole proteome turnover of a cell, but very few have been applied to archaea. In this chapter we describe a heavy isotope multilabeling method that allowed the successful analysis of relative protein synthesis and degradation rates on the proteome scale of the halophilic archaeon Haloferax volcanii. This method combines 15N and 13C isotope metabolic labeling with high-resolution mass spectrometry and data analysis tools (QuPE web-based platform) and could be applied to different archaea. © 2022. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.

Carotenoids are bioactive molecules known to promote human health. Many extreme halophilic archaea synthesize carotenoids, mainly represented by C