Lysine acetylation during oxidative stress response in the halophilic archaeon Haloferax volcanii

Abstract

Stress adaptation strategies have been a central topic of research in halophilic organisms due to biotechnological and astrobiological applications. This study is focused on how the halophilic archaeon Haloferax volcaniimay use lysine acetylation to regulate the oxidative stress response. Previous studies have shown that a) HOCl stress causes the lysine acetyltransferases Pat2:Pat1 ratios to increase and b) mutation of the lysine deacetylase sir2 gene renders cells hypertolerant to oxidative stress, suggesting this post translational modification system has a role during oxidative stress response. Immunoblotting experiments carried out in this study show an increase in lysine acetylation when glycerol‐grown cells are exposed to sodium hypochlorite. Mass spectrometry analysis of the lysine acetylome shows central metabolism pathways are modified under non‐treatment conditions. Of note during oxidative stress, a 2Fe‐2S ferredoxin (HVO_2995) was shown to be reduced in lysine acetylation levels suggesting an important role during oxidative stress response in the organism. These results now pave the way for a comprehensive quantitative mass spectrometry study to assess the global role of lysine acetylation during this oxidative stress response in the organism. Understanding this system can give us new answers into mechanisms of stress response in halophilic archaea. Expansion of this knowledge can provide a balanced evolutionary perspective of post translational modifications in living organisms.