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Dive into the research topics where Adriana Zagari is active.

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Featured researches published by Adriana Zagari.


PLOS ONE | 2012

Glucokinase (GCK) Mutations and Their Characterization in MODY2 Children of Southern Italy

Marina Capuano; Carmen M. García-Herrero; Nadia Tinto; Carla Carluccio; Valentina Capobianco; Iolanda Coto; Arturo Cola; Dario Iafusco; Adriana Franzese; Adriana Zagari; María Ángeles Navas; Lucia Sacchetti

Type 2 Maturity Onset Diabetes of the Young (MODY2) is a monogenic autosomal disease characterized by a primary defect in insulin secretion and hyperglycemia. It results from GCK gene mutations that impair enzyme activity. Between 2006 and 2010, we investigated GCK mutations in 66 diabetic children from southern Italy with suspected MODY2. Denaturing High Performance Liquid Chromatography (DHPLC) and sequence analysis revealed 19 GCK mutations in 28 children, six of which were novel: p.Glu40Asp, p.Val154Leu, p.Arg447Glyfs, p.Lys458_Cys461del, p.Glu395_Arg397del and c.580-2A>T. We evaluated the effect of these 19 mutations using bioinformatic tools such as Polymorphism Phenotyping (Polyphen), Sorting Intolerant From Tolerant (SIFT) and in silico modelling. We also conducted a functional study to evaluate the pathogenic significance of seven mutations that are among the most severe mutations found in our population, and have never been characterized: p.Glu70Asp, p.His137Asp, p.Phe150Tyr, p.Val154Leu, p.Gly162Asp, p.Arg303Trp and p.Arg392Ser. These seven mutations, by altering one or more kinetic parameters, reduced enzyme catalytic activity by >40%. All mutations except p.Glu70Asp displayed thermal-instability, indeed >50% of enzyme activity was lost at 50°C/30 min. Thus, these seven mutations play a pathogenic role in MODY2 insurgence. In conclusion, this report revealed six novel GCK mutations and sheds some light on the structure-function relationship of human GCK mutations and MODY2.


Prion | 2007

A Structural Overview of the Vertebrate Prion Proteins

Annalisa Pastore; Adriana Zagari

Among the large family of diseases caused by protein aggregation and misfolding is that associated to the Prion Protein (PrP). This is a small extracellular membrane-anchored molecule of yet unknown function. Understanding how PrP folds both into its cellular and pathological forms is thought to be crucial for explaining protein misfolding in general and the specific role of PrP in disease. Since the first structure determination, an increasing number of structural studies of PrP have become available, showing that the protein is formed by a flexible N-terminal region and a highly conserved globular C-terminal domain. We review here the current knowledge on PrP structure. We focus on vertebrate PrPs and analyse in detail the similarities and the differences among the coordinates of the C-terminal domain of PrP from different species, in search for understanding the mechanism of disease-causing mutations and the molecular bases of species barrier.


Biochimica et Biophysica Acta | 2008

The crystal structure of the superoxide dismutase from Helicobacter pylori reveals a structured C-terminal extension

Luciana Esposito; Anke Seydel; Rosa Aiello; Giosué Sorrentino; Laura Cendron; Giuseppe Zanotti; Adriana Zagari

Superoxide dismutases (SODs) are key enzymes for fighting oxidative stress. Helicobacter pylori produces a single SOD (HpSOD) which contains iron. The structure of this antioxidant protein has been determined at 2.4 A resolution. It is a dimer of two identical subunits with one iron ion per monomer. The protein shares 53% sequence identity with the corresponding enzyme from Escherichia coli. The model is compared with those of other dimeric Fe-containing SODs. HpSOD shows significant differences in relation to other SODs, the most important being an extended C-terminal tail. This structure provides a model for closely related sequences from species such as Campylobacter, where no structures are currently known. The structure of extended carboxyl termini is discussed in light of putative functions it may serve.


FEBS Letters | 2008

In HspA from Helicobacter pylori vicinal disulfide bridges are a key determinant of domain B structure

Salvatore Loguercio; Cyril Dian; Angela Flagiello; Alessandra Scannella; Piero Pucci; Laurent Terradot; Adriana Zagari

Helicobacter pylori produces a heat shock protein A (HspA) that is unique to this bacteria. While the first 91 residues (domain A) of the protein are similar to GroES, the last 26 (domain B) are unique to HspA. Domain B contains eight histidines and four cysteines and was suggested to bind nickel. We have produced HspA and two mutants: Cys94Ala and Cys94Ala/Cys111Ala and identified the disulfide bridge pattern of the protein. We found that the cysteines are engaged in three disulfide bonds: Cys51/Cys53, Cys94/Cys111 and Cys95/Cys112 that result in a unique closed loop structure for the domain B.


Archive | 1994

Subunit Assembly in Bovine Seminal Ribonuclease

Lelio Mazzarella; Luigi Vitagliano; Adriana Zagari; S. Capasso

The association of subunits in an oligomeric protein is a widespread phenomenon in the cellular organization, which promotes several advantages. A most important one is the regulation of catalytic activity through cooperative effects, mediated by specific interactions at subunit interface. Crystallographic studies of homologous proteins, which occur in different aggregation states, indicate that in most cases the globular monomer is stable on its own and is only marginally altered when it forms an oligomeric molecule. A notable exception is provided by some members of the ribonuclease family [1], which on aggregation show a substantial rearrangement of the tertiary structure of the monomer. The modification affects significantly the functionality of the active site, although the overall architecture of the site remains basically unchanged.


International Journal of Peptide and Protein Research | 2009

Type II‘β-bend conformation of tert.-butyloxycarbonyl-L-amino-succinyl-L-alanyl-glycine methyl ester in the solid state

S. Capasso; Lelio Mazzarella; Filomena Sica; Adriana Zagari


International Journal of Peptide and Protein Research | 2009

Preferred conformations of tert.-butyloxycarbonyl-L-aminosuccinyl-glycyl-glycine methyl ester in the solid and solution state

S. Capasso; Carlo Mattia; Lelio Mazzarella; Adriana Zagari


International Journal of Peptide and Protein Research | 2009

Conformational properties of aminosuccinyl peptides: crystal structure and conformational analysis of tert.-butyloxycarbonyl-L-aminosuccinyl-glycine methyl ester

S. Capasso; Carlo Mattia; Prof.Lelio Mazzarella; Adriana Zagari


International Journal of Peptide and Protein Research | 2009

Chiroptical properties of aminosuccinyl peptides

S. Capasso; Lelio Mazzarella; Filomena Sica; Adriana Zagari


International Journal of Peptide and Protein Research | 2009

Conformationally restrained peptides: crystal structure of tert-butyloxycarbonyl-L-alanyl-D-alanyl-D-aminosuccinyl-glycyl-L- alanine methyl ester.

D. Demasi; S. Capasso; Filomena Sica; Adriana Zagari

Collaboration


Dive into the Adriana Zagari's collaboration.

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S. Capasso

University of Naples Federico II

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Lelio Mazzarella

University of Naples Federico II

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Carlo Mattia

University of Naples Federico II

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Filomena Sica

University of Naples Federico II

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Sante Capasso

Seconda Università degli Studi di Napoli

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Adriana Franzese

University of Naples Federico II

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Alessandra Scannella

University of Naples Federico II

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Angela Flagiello

University of Naples Federico II

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Arturo Cola

University of Naples Federico II

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