A Rigidifying Salt-Bridge Favors the Activity of Thermophilic Enzyme at High Temperatures at the Expense of Low-Temperature Activity

Although enzymes from thermophiles thriving in hot habitats are more stable than their mesophilic homologs, they are often less active at low temperatures. One theory suggests that extra stabilizing interactions found in thermophilic enzymes may increase their rigidity and decrease enzymatic activity at lower temperatures. We used acylphosphatase as a model to study how flexibility affects enzymatic activity. This enzyme has a unique structural feature in that an invariant arginine residue, which takes part in catalysis, is restrained by a salt-bridge in the thermophilic homologs but not in its mesophilic homologs. Here, we demonstrate the trade-offs between flexibility and enzymatic activity by disrupting the salt-bridge in a thermophilic acylphosphatase and introducing it in the mesophilic human homolog. Our results suggest that the salt-bridge is a structural adaptation for thermophilic acylphosphatases as it entropically favors enzymatic activity at high temperatures by restricting the flexibility of the active-site residue. However, at low temperatures the salt-bridge reduces the enzymatic activity because of a steeper temperature-dependency of activity

Forecasting biological impacts of climate change for risk assessment in fisheries and aquaculture, the ClimeFish approach

4th European Climate Change Adaptation Conference, Lisbon, 28-31 MAy 2019ClimeFish is an on-going H2020 project committed to the study of the impacts of climate change on freshwater and marine fisheries and aquaculture across Europe. Regional climate models (RCM) feed biological models to forecast the biomass/production and distribution patterns of the target species studied by ClimeFish under the expected climate conditions in Europe by year 2050. This presentation focuses on the seven case studies for which risks and opportunities were identified, allowing the development of strategies to mitigate risks and utilize opportunitiesPeer reviewe