Speakers: Ramon Crehuet and Josep M. Anglada
Data: 17th February 2021
Time: 12 pm
CSIC Conecta link: https://conectaha.csic.es/b/ana-ow1-q5v-kgd
Molecular insights into polyglutamine diseases – Ramon Creuhet
Several diseases, such as Huntington disease, are caused by long polyglutamine tracts in disordered regions of proteins. Contrary to expectations these tracts can form stable helices depending on their flanking aminoacids. Combining experimental and computational techniques, we showed that an unconventional hydrogen bond is resposible for the stabilization of the helices. The stability of this bond is determined by the shielding effect of neighbouring residues, thus explaining the role of the flanking regions. The helicity of the tract may affect its aggregation properties, which in turn may be related to the onset of the polyglutamine disorders.
Atmospheric Chemistry. A view from theoretical and computational chemistry – Josep M. Anglada
There is a huge amount of species that are emitted to the Earth’s atmosphere from both,biogenic and anthropogenic sources, which must be removed to prevent accumulation in the air. The removal processes basically involve dry and wet deposition and oxidation reactions, but solar radiation plays also an important role. Several of these species are greenhouse gases and contribute to climate change whereas other compounds act as pollutants having a direct impact on human health.
The Earth’s atmosphere is an oxidant environment and therefore oxidation reactions are widespread. Ozone (O3), hydrogen peroxide (H2O2), the associated hydroxyl and hydroperoxyl radicals (HOx = OH and HO2), and nitrate radical (NO3) are the main oxidants, and among them, hydroxyl radical is the most powerful and keep the air clean. Its chemistry is driven by a complex system of chain reactions involving nitrogen oxides, hydroxyl and hydroperoxide radicals, alkoxy and peroxy radicals and ozone, among other species. Moreover, the presence of clouds has a direct effect in the atmospheric chemical composition. Many atmospheric trace gases are adsorbed and/or absorbed into the cloud droplets making the chemistry of the atmosphere much more complex and richer.
The first part of this talk will be devoted to the chemistry of hydroxyl radical. With several examples we will show different reactivity modes that can be extended to the reactivity of other radicals. In the second part we will show how the photochemistry at the air-water (air-clouds) interface produces an unexpected enhancement in the formation of OH radicals which may have impact at global scale.
IQAC-CSIC Communication
