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Articles by Alejandro Giorgetti in JoVE
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Flusso di lavoro globale per l'identificazione del genoma e la Meta-analisi di espressione della famiglia genica ATL E3 ubiquitina ligasi a Grapevine
Pietro Ariani*1, Elodie Vandelle*1, Darren Wong2, Alejandro Giorgetti1, Andrea Porceddu3, Salvatore Camiolo3, Annalisa Polverari1
1Dipartimento di Biotecnologie, Università degli Studi di Verona, 2Ecology and Evolution, Research School of Biology, The Australian National University, 3Dipartimento di Agraria, SACEG, Università degli Studi di Sassari
Questo articolo descrive la procedura per l'identificazione e la caratterizzazione di una famiglia di geni a grapevine applicato alla famiglia di Arabidopsis Tóxicos in Levadura (ATL) E3 ubiquitina ligasi.
Other articles by Alejandro Giorgetti on PubMed
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Structural Modeling of G-protein Coupled Receptors: An Overview on Automatic Web-servers
The International Journal of Biochemistry & Cell Biology.
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Pubmed ID: 27102413 Despite the significant efforts and discoveries during the last few years in G protein-coupled receptor (GPCR) expression and crystallization, the receptors with known structures to date are limited only to a small fraction of human GPCRs. The lack of experimental three-dimensional structures of the receptors represents a strong limitation that hampers a deep understanding of their function. Computational techniques are thus a valid alternative strategy to model three-dimensional structures. Indeed, recent advances in the field, together with extraordinary developments in crystallography, in particular due to its ability to capture GPCRs in different activation states, have led to encouraging results in the generation of accurate models. This, prompted the community of modelers to render their methods publicly available through dedicated databases and web-servers. Here, we present an extensive overview on these services, focusing on their advantages, drawbacks and their role in successful applications. Future challenges in the field of GPCR modeling, such as the predictions of long loop regions and the modeling of receptor activation states are presented as well.
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Residues in the Distal Heme Pocket of Arabidopsis Non-Symbiotic Hemoglobins: Implication for Nitrite Reductase Activity
International Journal of Molecular Sciences.
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Pubmed ID: 27136534 It is well-established that plant hemoglobins (Hbs) are involved in nitric oxide (NO) metabolism via NO dioxygenase and/or nitrite reductase activity. The ferrous-deoxy Arabidopsis Hb1 and Hb2 (AHb1 and AHb2) have been shown to reduce nitrite to NO under hypoxia. Here, to test the hypothesis that a six- to five-coordinate heme iron transition might mediate the control of the nitrite reduction rate, we examined distal pocket mutants of AHb1 and AHb2 for nitrite reductase activity, NO production and spectroscopic features. Absorption spectra of AHbs distal histidine mutants showed that AHb1 mutant (H69L) is a stable pentacoordinate high-spin species in both ferrous and ferric states, whereas heme iron in AHb2 mutant (H66L) is hexacoordinated low-spin with Lys69 as the sixth ligand. The bimolecular rate constants for nitrite reduction to NO were 13.3 ± 0.40, 7.3 ± 0.5, 10.6 ± 0.8 and 171.90 ± 9.00 M(-1)·s(-1) for AHb1, AHb2, AHb1 H69L and AHb2 H66L, respectively, at pH 7.4 and 25 °C. Consistent with the reductase activity, the amount of NO detected by chemiluminescence was significantly higher in the AHb2 H66L mutant. Our data indicate that nitrite reductase activity is determined not only by heme coordination, but also by a unique distal heme pocket in each AHb.
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Protein Aggregation and Molecular Crowding: Perspectives From Multiscale Simulations
International Review of Cell and Molecular Biology.
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Pubmed ID: 28109331 Cells are extremely crowded environments, thus the use of diluted salted aqueous solutions containing a single protein is too simplistic to mimic the real situation. Macromolecular crowding might affect protein structure, folding, shape, conformational stability, binding of small molecules, enzymatic activity, interactions with cognate biomolecules, and pathological aggregation. The latter phenomenon typically leads to the formation of amyloid fibrils that are linked to several lethal neurodegenerative diseases, but that can also play a functional role in certain organisms. The majority of molecular simulations performed before the last few years were conducted in diluted solutions and were restricted both in the timescales and in the system dimensions by the available computational resources. In recent years, several computational solutions were developed to get close to physiological conditions. In this review we summarize the main computational techniques used to tackle the issue of protein aggregation both in a diluted and in a crowded environment.
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