| 1. |
- Scian, Michele, et al.
(author)
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Comparison of epsilon- and delta-class glutathione S-transferases : the crystal structures of the glutathione S-transferases DmGSTE6 and DmGSTE7 from Drosophila melanogaster
- 2015
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In: Acta Crystallographica Section D. - 0907-4449 .- 1399-0047. ; 71, s. 2089-2098
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Journal article (peer-reviewed)abstract
- Cytosolic glutathione transferases (GSTs) comprise a large family of enzymes with canonical structures that diverge functionally and structurally among mammals, invertebrates and plants. Whereas mammalian GSTs have been characterized extensively with regard to their structure and function, invertebrate GSTs remain relatively unstudied. The invertebrate GSTs do, however, represent potentially important drug targets for infectious diseases and agricultural applications. In addition, it is essential to fully understand the structure and function of invertebrate GSTs, which play important roles in basic biological processes. Invertebrates harbor delta-and epsilon-class GSTs, which are not found in other organisms. Drosophila melanogaster GSTs (DmGSTs) are likely to contribute to detoxication or antioxidative stress during development, but they have not been fully characterized. Here, the structures of two epsilon-class GSTs from Drosophila, DmGSTE6 and DmGSTE7, are reported at 2.1 and 1.5 angstrom resolution, respectively, and are compared with other GSTs to identify structural features that might correlate with their biological functions. The structures of DmGSTE6 and DmGSTE7 are remarkably similar; the structures do not reveal obvious sources of the minor functional differences that have been observed. The main structural difference between the epsilon-and delta-class GSTs is the longer helix (A8) at the C-termini of the epsilon-class enzymes.
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| 2. |
- Trave, Enrico, et al.
(author)
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Control of silver clustering for broadband Er3+ luminescence sensitization in Er and Ag co-implanted silica
- 2018
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In: Journal of Luminescence. - : Elsevier. - 0022-2313 .- 1872-7883. ; 197, s. 104-111
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Journal article (peer-reviewed)abstract
- In this work, the optical properties of Er and Ag co-implanted silica slabs were investigated in order to shed light on the observed improvement of the rare-earth emission properties through a sensitization process activated by Ag implantation. A full ion implantation approach was adopted since it represents an effective way to create a thin doped layer, where luminescent Er ions can interact with Ag-related sensitizing species. The results evidenced that the sensitization process is effectively promoted in presence of Ag ultra-small structures, like few-atom aggregates or multimers, which can be already formed at the early stages of the metal clustering process. On the other hand, the precipitation of large, plasmonic clusters, occurring at high temperature post-Ag implantation annealing, produces a decrease of the fluorescence enhancement effect. Furthermore, it is suggested that the overall sensitization mechanism originates from an Ag-Er energy transfer that determines the possibility of a broadband photostimulation of the rare-earth ions, even by pumping in non-resonant excitation condition. Thanks to these features, the investigated Er and Ag co-implanted system can be considered for the realization of high-performing optical amplifiers in waveguide.
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