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Global protein oxidation profiling to understand aging and fitness of microorganisms

  报告人:Prof. Ansgar Poetsch  

  单位:德国波鸿大学  

  时间:2016530 下午1500  

  地点:微生物所A203会议室  

  主持人: 刘双江 研究员  

  摘要: Free radicals, such as reactive oxygen species (ROS) are produced in microorganisms or are encountered from the environment. Their damage on biomolecules should affect the fitness, and in the long term the aging of an organism, as for instance postulated by the popular free radical biology of aging. My group has developed new proteomics workflows for global, quantitative and un-targeted analyses of oxidative protein modifications to better understand their physiological impact. Two examples from recent works will be presented: 

  1.Verification of the free radical biology of aging with the fungal model system Podospora anserina 

  A large scale, unbiased oxidative modification-centric study for mitochondrial aging allowed the comprehensive quantification of 2352 protein species and 23 different oxidative amino acid modifications. For 746 proteins unmodified and oxidatively modified species were detected. For the majority of proteins a positive correlation of changes in protein amount and oxidative damage, and rarely age-related increases in protein oxidation were noticed. Our data suggest that P. anserina is efficiently capable to compensate ROS-induced protein damage during aging as long as protein de-novo synthesis is functioning, ultimately leading to an overall constant relationship between damaged und undamaged protein species. In contradiction to the ROS theory, our results do not confirm massive increase in protein oxidation during aging and rather suggest a functional protein homeostasis mechanism even at high age. 

  2. Impact of ROS exposure on the proteome of Corynebacterium glutamicum and strategies for increased resistance 

  Continuous formation of reactive oxygen species (ROS) leads to damage of biomolecules, e.g. protein oxidation. This can occur also during industrial processes, such as amino acid production with C. glutamicum. We tested two approaches for increasing ROS resistance of this organism, namely a) heterologous expression of more ROS-tolerant enzymes, and b) over-expression of repair enzymes, i.e. methione sulfoxide reductases (MSRs). However, both strategies did not result in a significant increase in ROS resistance, which may be explained by the fact that the organism is already very resistant against ROS, in particular hydrogen peroxide. To verify, if MSRs are indeed important to repair oxidized proteins, proteomics of a KO mutant and the WT exposed to hypochloride was pursued. This could be confirmed, since (transport) proteins of the iron homeostasis and the cysteine/methionine metabolism were up-regulated in the double deletion mutant after stress induction, and certain proteins displayed increased oxidation.  

  欢迎老师和同学们积极参加!  

 
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