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Baglivo I.,Biological and Pharmaceutical science and Technologies | Palmieri M.,Biological and Pharmaceutical science and Technologies | Rivellino A.,Biological and Pharmaceutical science and Technologies | Netti F.,Biological and Pharmaceutical science and Technologies | And 12 more authors.
Biochimica et Biophysica Acta - Proteins and Proteomics | Year: 2014

The specific arrangement of secondary elements in a local motif often totally relies on the formation of coordination bonds between metal ions and protein ligands. This is typified by the ~ 30 amino acid eukaryotic zinc finger motif in which a β-sheet and an α-helix are clustered around a zinc ion by various combinations of four ligands. The prokaryotic zinc finger domain (found in the Ros protein from Agrobacterium tumefaciens) is different from the eukaryotic counterpart as it consists of 58 amino acids arranged in a βββαα topology stabilized by a 15-residue hydrophobic core. Also, this domain tetrahedrally coordinates zinc and unfolds in the absence of the metal ion. The characterization of proteins belonging to the Ros homologs family has however shown that the prokaryotic zinc finger domain can overcome the metal requirement to achieve the same fold and DNA-binding activity. In the present work, two zinc-lacking Ros homologs (Ml4 and Ml5 proteins) have been thoroughly characterized using bioinformatics, biochemical and NMR techniques. We show how in these proteins a network of hydrogen bonds and hydrophobic interactions surrogate the zinc coordination role in the achievement of the same functional fold. © 2013 Published by Elsevier B.V. Source


Scognamiglio M.,Biological and Pharmaceutical science and Technologies | D'Abrosca B.,Biological and Pharmaceutical science and Technologies | Severino V.,Biological and Pharmaceutical science and Technologies | Chambery A.,Biological and Pharmaceutical science and Technologies | And 2 more authors.
Phytochemistry Letters | Year: 2014

Two new acylated drimane sesquiterpenoid glucosides, saxifragoside A and B, have been isolated from the methanol extract of Petrorhagia saxifraga, a perennial herbaceous plant typical of the Mediterranean vegetation. The structures of these compounds have been elucidated on the basis of extensive 2D NMR spectroscopic analyses, including COSY, TOCSY, NOESY, HSQC, CIGAR-HMBC, H2BC and HSQC-TOCSY, along with Q-TOF HRMS2 analysis. As drimane glucosides have already been reported in other plants of Petrorhagia genus, they could represent a useful chemotaxonomic marker for this genus. © 2013 Published by Elsevier B.V. Source


Malgieri G.,Biological and Pharmaceutical science and Technologies | Palmieri M.,Biological and Pharmaceutical science and Technologies | Esposito S.,Biological and Pharmaceutical science and Technologies | Maione V.,Biological and Pharmaceutical science and Technologies | And 13 more authors.
Metallomics | Year: 2014

Given the similar chemical properties of zinc and cadmium, zinc finger domains have been often proposed as mediators of the toxic and carcinogenic effects exerted by this xenobiotic metal. The effects of zinc replacement by cadmium in different eukaryotic zinc fingers have been reported. In the present work, to evaluate the effects of such substitution in the prokaryotic zinc finger, we report a detailed study of its functional and structural consequences on the Ros DNA binding domain (Ros87). We show that this protein, which bears important structural differences with respect to the eukaryotic domains, appears to structurally tolerate the zinc to cadmium substitution and the presence of cadmium does not affect the DNA binding activity of the protein. Moreover, we show for the first time how zinc to cadmium replacement can also take place in a cellular context. Our findings both complement and extend previous results obtained for different eukaryotic zinc fingers, suggesting that metal substitution in zinc fingers may be of relevance to the toxicity and/or carcinogenicity mechanisms of this metal. This journal is © 2014 The Royal Society of Chemistry. Source

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