Biomedical subjects

Andrea Scaloni

Publications and source records attributed to Andrea Scaloni.

58 records · Page 4Linked to original sources

PubMed2002

A new syringopeptin produced by bean strains of Pseudomonas syringae pv. syringae.

Two strains (B728a and Y37) of the phytopathogenic bacterium Pseudomonas syringae pv. syringae isolated from bean (Phaseolus vulgaris) plants were shown to produce in culture both syringomycin, a lipodepsinonapeptide secreted by the majority of the strains of the bacterium, and a new form of syringopeptin, SP(22)Phv. The structure of the latter metabolite was elucidated by the combined use of mass spectrometry (MS), nuclear magnetic resonance (NMR) spectroscopy and chemical procedures. Comparative phytotoxic and antimicrobial assays showed that SP(22)Phv did not differ substantially from the previously characterized syringopeptin 22 (SP(22)) as far as toxicity to plants was concerned, but was less active in inhibiting the growth of the test fungi Rhodotorula pilimanae and Geotrichum candidum and of the Gram-positive bacterium Bacillus megaterium.

Amino Acid Sequence↗

PubMed2002

Purified box C/D snoRNPs are able to reproduce site-specific 2'-O-methylation of target RNA in vitro.

Small nucleolar RNAs (snoRNAs) are associated in ribonucleoprotein particles localized to the nucleolus (snoRNPs). Most of the members of the box C/D family function in directing site-specific 2'-O-methylation of substrate RNAs. Although the selection of the target nucleotide requires the antisense element and the conserved box D or D' of the snoRNA, the methyltransferase activity is supposed to reside in one of the protein components. Through protein tagging of a snoRNP-specific factor, we purified to homogeneity box C/D snoRNPs from the yeast Saccharomyces cerevisiae. Mass spectrometric analysis demonstrated the presence of Nop1p, Nop58p, Nop56p, and Snu13p as integral components of the particle. We show that purified snoRNPs are able to reproduce the site-specific methylation pattern on target RNA and that the predicted S-adenosyl-L-methionine-binding region of Nop1p is responsible for the catalytic activity.

Binding Sites↗

PubMedDate not supplied

Proteins as biomarkers of oxidative/nitrosative stress in diseases: the contribution of redox proteomics.

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) contribute to the pathogenesis and/or progression of several human diseases. Proteins are important molecular signposts of oxidative/nitrosative damage. However, it is generally unresolved whether the presence of oxidatively/nitrosatively modified proteins has a causal role or simply reflects secondary epiphenomena. Only direct identification and characterization of the modified protein(s) in a given pathophysiological condition can decipher the potential roles played by ROS/RNS-induced protein modifications. During the last few years, mass spectrometry (MS)-based technologies have contributed in a significant way to foster a better understanding of disease processes. The study of oxidative/nitrosative modifications, investigated by redox proteomics, is contributing to establish a relationship between pathological hallmarks of disease and protein structural and functional abnormalities. MS-based technologies promise a contribution in a new era of molecular medicine, especially in the discovery of diagnostic biomarkers of oxidative/nitrosative stress, enabling early detection of diseases. Indeed, identification and characterization of oxidatively/nitrosatively modified proteins in human diseases has just begun.

Disease↗

PubMedDate not supplied

Proteomic analysis of erythrocyte membranes by soft Immobiline gels combined with differential protein extraction.

Improvements in proteome analysis of erythrocyte membrane proteins by two-dimensional electrophoresis are here reported. In particular, a differential extraction procedure was set up allowing separation of integral membrane proteins from peripheral species. Moreover, the use of dilute Immobiline gels (down to as low as 3% T matrix) permitted a better penetration and transfer inside the gel of proteins with large M(r). These protocol modifications, combined with sample delipidation and alkylation prior to electrophoresis, which prevented generation of homo- and hetero-oligomers following disulfide scrambling phenomena, allowed the display of more than 500 spots in the pI/M(r) plane. Among those, noteworthy was the presence of high levels of filamentous proteins, such as alpha-spectrin and ankyrins, or integral membrane proteins, such as band 3, band 4.1 and 4.2, not displayed or barely present in other maps exploiting immobilized pH gradients in the first dimension. Accordingly, our results show that this 2D mapping technique is a valuable tool in exploring pathologies related to genetic defects associated to membrane proteins.

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