35,693 research outputs found
Rendiconto online della Soc.Geol.Ital.
No full textIn this study we provide a general structural picture of Ischia
island shallow crust to model the processes occurring at shallow
depth, by using geological, geophysical, historical seismicity data
and analytical structural models of the island (PENTA &
CONFORTO, 1951; CUBELLIS & LUONGO, 1998; CUBELLIS et alii,
2004; CARLINO et alii, 2006; PAOLETTI et alii, 2009; VEZZOLI et
alii., 2009; SBRANA et alii, 2009). These studies support the
hypothesis of the presence of a shallow laccolith, which is
responsible of the resurgence of Mt. Epomeo, following the
Green Tuff eruption, volcanic activity and seismicity...PublishedPisa3.5. Geologia e storia dei vulcani ed evoluzione dei magmi3.6. Fisica del vulcanismoope
A thermodynamic assay to test pharmacological chaperones for Fabry disease.
No full textBackground The majority of the disease-causing mutations affect protein stability, but not functional sites and are amenable, in principle, to be treated with pharmacological chaperones. These drugs enhance the thermodynamic stability of their targets. Fabry disease, a disorder caused by mutations in the gene encoding lysosomal alpha-galactosidase, represents an excellent model system to develop experimental protocols to test the efficiency of such drugs. Methods The stability of lysosomal alpha-galactosidase under different conditions was studied by urea-induced unfolding followed by limited proteolysis and Western blotting. Results We measured the concentration of urea needed to obtain half-maximal unfolding because this parameter represents an objective indicator of protein stability. Conclusions Urea-induced unfolding is a versatile technique that can be adapted to cell extracts containing tiny amounts of wild-type or mutant proteins. It allows testing of protein stability as a function of pH, in the presence or in the absence of drugs. Results are not influenced by the method used to express the protein in transfected cells. General significance Scarce and dispersed populations pose a problem for the clinical trial of drugs for rare diseases. This is particularly true for pharmacological chaperones that must be tested on each mutation associated with a given disease. Diverse in vitro tests are needed. We used a method based on chemically induced unfolding as a tool to assess whether a particular Fabry mutation is responsive to pharmacological chaperones, but, by no means is our protocol limited to this disease
An intron-less βγ-crystallin-type gene from the sponge Geodia cydonium
No full textWe report the cloning of a gene encoding a βγ-crystallin-type protein from a porifera, the Geodia cydonium sponge. The data provide direct, conclusive evidence of the existence of such a gene in the genome of an early diverged metazoan. The cloned gene is found to contain no introns, while proto-splice sites are identified in the nucleotide sequence at positions where introns are located in homologous, very recently diverged vertebrate genes. These findings are discussed in the light of the debate between the introns-late and introns-early theories. © 2002 Elsevier Science B.V. All rights reserved
Conformational Response to Ligand Binding in Phosphomannomutase2: INSIGHTS INTO INBORN GLYCOSYLATION DISORDER
No full textThe most common glycosylation disorder is caused by mutations in the gene encoding phosphomannomutase2, producing a disease still without a cure. Phosphomannomutase2, a homodimer in which each chain is composed of two domains, requires a bisphosphate sugar (either mannose or glucose) as activator, opening a possible drug design path for therapeutic purposes. The crystal structure of human phosphomannomutase2, however, lacks bound substrate and a key active site loop. To speed up drug discovery, we present here the first structural model of a bisphosphate substrate bound to human phosphomannomutase2. Taking advantage of recent developments in all-atom simulation techniques in combination with limited and site-directed proteolysis, we demonstrated that α-glucose 1,6-bisphosphate can adopt two low energy orientations as required for catalysis. Upon ligand binding, the two domains come close, making the protein more compact, in analogy to the enzyme in the crystals from Leishmania mexicana. Moreover, proteolysis was also carried out on two common mutants, R141H and F119L. It was an unexpected finding that the mutant most frequently found in patients, R141H, although inactive, does bind α-glucose 1,6-bisphosphate and changes conformation
Bioinformatics tools for marine biotechnology: A practical tutorial with a metagenomic approach
No full textBackground: Bioinformatics has pervaded all fields of biology and has become an indispensable tool for almost all research projects. Although teaching bioinformatics has been incorporated in all traditional life science curricula, practical hands-on experiences in tight combination with wet-lab experiments are needed to motivate students. Results: We present a tutorial that starts from a practical problem: finding novel enzymes from marine environments. First, we introduce the idea of metagenomics, a recent approach that extends biotechnology to non-culturable microbes. We presuppose that a probe for the screening of metagenomic cosmid library is needed. The students start from the chemical structure of the substrate that should be acted on by the novel enzyme and end with the sequence of the probe. To attain their goal, they discover databases such as BRENDA and programs such as BLAST and Clustal Omega. Students' answers to a satisfaction questionnaire show that a multistep tutorial integrated into a research wet-lab project is preferable to conventional lectures illustrating bioinformatics tools. Conclusion: Experimental biologists can better operate basic bioinformatics if a problem-solving approach is chosen
Pharmacological chaperones: A therapeutic approach for diseases caused by destabilizing missense mutations
No full textThe term “pharmacological chaperone” was introduced 20 years ago. Since then the approach with this type of drug has been proposed for several diseases, lysosomal storage disorders representing the most popular targets. The hallmark of a pharmacological chaperone is its ability to bind a protein specifically and stabilize it. This property can be beneficial for curing diseases that are associated with protein mutants that are intrinsically active but unstable. The total activity of the affected proteins in the cell is lower than normal because they are cleared by the quality control system. Although most pharmacological chaperones are reversible competitive inhibitors or antagonists of their target proteins, the inhibitory activity is neither required nor desirable. This issue is well documented by specific examples among which those concerning Fabry disease. Direct specific binding is not the only mechanism by which small molecules can rescue mutant proteins in the cell. These drugs and the properly defined pharmacological chaperones can work together with different and possibly synergistic modes of action to revert a disease phenotype caused by an unstable protein
Heterodimerization of Two Pathological Mutants Enhances the Activity of Human Phosphomannomutase2.
No full textThe most frequent disorder of glycosylation is due to mutations in the gene encoding phosphomannomutase2 (PMM2-CDG). For this disease, which is autosomal and recessive, there is no cure at present. Most patients are composite heterozygous and carry one allele encoding an inactive mutant, R141H, and one encoding a hypomorphic mutant. Phosphomannomutase2 is a dimer. We reproduced composite heterozygosity in vitro by mixing R141H either with the wild type protein or the most common hypomorphic mutant F119L and compared the quaternary structure, the activity and the stability of the heterodimeric enzymes. We demonstrated that the activity of R141H/F119L heterodimers in vitro, which reproduces the protein found in patients, has the same activity of wild type/R141H, which reproduces the protein found in healthy carriers. On the other hand the stability of R141H/F119L appears to be reduced both in vitro and in vivo. These findings suggest that a therapy designed to enhance protein stability such as those based on pharmacological chaperones or modulation of proteostasis could be beneficial for PMM2-CDG patients carrying R141H/F119L genotype as well as for other genotypes where protein stability rather than specific activity is affected by mutations
Antitumor Action of Seminal Ribonuclease, Its Dimeric Structure, and Its Resistance to the Cytosolic Ribonuclese Inhibitor
No full textThe antitumor Action of Seminal Ribonuclease is strictly dependent on its Dimeric Structure, which induce its Resistance to the Ribonuclese Inhibito
Congenital disorders of glycosylation: narration of a story through its patents
No full textCongenital disorders of glycosylation are a group of more than 160 rare genetic defects in protein and lipid glycosylation. Since the first clinical report in 1980 of PMM2-CDG, the most common CDG worldwide, research made great strides, but nearly all of them are still missing a cure. CDG diagnosis has been at a rapid pace since the introduction of whole-exome/whole-genome sequencing as a diagnostic tool. Here, we retrace the history of CDG by analyzing all the patents associated with the topic. To this end, we explored the Espacenet database, extracted a list of patents, and then divided them into three major groups: (1) Drugs/therapeutic approaches for CDG, (2) Drug delivery tools for CDG, (3) Diagnostic tools for CDG. Despite the enormous scientific progress experienced in the last 30 years, diagnostic tools, drugs, and biomarkers are still urgently needed
Why does SARS-CoV-2 hit in different ways? Host genetic factors can influence the acquisition or the course of COVID-19
No full textThe identification of high-risk factors for the infection by SARS-CoV-2 and the negative outcome of COVID-19 is crucial. The genetic background of the host might account for individual responses to SARS-CoV-2 infection besides age and comorbidities. A list of candidate polymorphisms is needed to drive targeted screens, given the existence of frequent polymorphisms in the general population. We carried out text mining in the scientific literature to draw up a list of genes referable to the term “SARS-CoV*“. We looked for frequent mutations that are likely to affect protein function in these genes. Ten genes, mostly involved in innate immunity, and thirteen common variants were identified, for some of these the involvement in COVID-19 is supported by publicly available epidemiological data. We looked for available data on the population distribution of these variants and we demonstrated that the prevalence of five of them, Arg52Cys (rs5030737), Gly54Asp (rs1800450) and Gly57Glu (rs1800451) in MBL2, Ala59Thr (rs25680) in CD27, and Val197Met (rs12329760) in TMPRSS2, correlates with the number of cases and/or deaths of COVID-19 observed in different countries. The association of the TMPRSS2 variant provides epidemiological evidence of the usefulness of transmembrane protease serine 2 inhibitors for the cure of COVID-19. The identified genetic variants represent a basis for the design of a cost-effective assay for population screening of genetic risk factors in the COVID-19 pandemic
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