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474 results on '"Sica, Filomena"'

102. DOMAIN SWAPPING IN BOVINE SEMINAL RIBONUCLEASE: ROLE OF THE INTERSUBUNIT INTERFACE

Author

MERLINO, ANTONELLO, ERCOLE, CARMINE, SICA, FILOMENA, MAZZARELLA, LELIO, PICONE, DELIA, DI FIORE, ANNA, Merlino, Antonello, Ercole, Carmine, Sica, Filomena, Mazzarella, Lelio, Picone, Delia, and DI FIORE, Anna

Subjects
BS-RNase, structural elements exchange, intersubunit interface
Abstract

The effects of selected mutations at the O-interface on the equilibrium between the MxM and M=M forma of bovine seminal ribonuclease have been studied.

Published
2005

105. DOMAIN SWAPPING IN BOVINE SEMINAL RIBONUCLEASE: ROLE OF THE HINGE LOOP

Author

ERCOLE, CARMINE, SICA, FILOMENA, MAZZARELLA, LELIO, FRANZESE, MARISA, PICONE, DELIA, TOMASELLI, SIMONA, A. DI FIORE, Ercole, Carmine, Sica, Filomena, Mazzarella, Lelio, Franzese, Marisa, Picone, Delia, A., DI FIORE, and Tomaselli, Simona

Subjects
hinge peptide, bovine seminal ribonuclease, domain swapping
Abstract

The relative insesitivity of the swapping tendency of bovine seminal ribonuclease to the substitutions in the hinge peptide has been rationalized in terms of the unique features of this enzyme.

Published
2005

110. EFFECT OF POINT MUTATION OF THE HIGHLY RIGID STRUCTURE OF ONCONASE

Author

A. DI FIORE, CARANNANTE, A., NOTOMISTA, E., DI DONATO, MERLINO, ANTONELLO, SICA, FILOMENA, MAZZARELLA, LELIO, A., DI FIORE, Merlino, Antonello, Sica, Filomena, Mazzarella, Lelio, Carannante, A., Notomista, E., and Di, Donato

Subjects
Cancer chemiotherapy, Onconase variant, thermal stability
Abstract

This study provides the molecular bases to explain the lower catalytic activity of ONC compared to RNase A.

Published
2004

112. STRUCTURAL BASIS OF DOMAIN SWAPPING IN BOVINE SEMINAL RIBONUCLEASE: A HOMOLOGY MUTATION APPROACH

Author

DI FIORE, ANNA, ERCOLE, CARMINE, SICA, FILOMENA, MAZZARELLA, LELIO, FRANZESE, MARISA, PICONE, DELIA, DI FIORE, Anna, Ercole, Carmine, Sica, Filomena, Mazzarella, Lelio, Franzese, Marisa, and Picone, Delia

Subjects
bovine seminal ribonuclease, homology mutation, domain swapping
Abstract

The swapping of BS-RNase terminal arms has studied by replacing the residues of the hinge peptide with the corresponding ones of RNase A.

Published
2004

128. ATOMIC RESOLUTION STRUCTURES OF RNASE A AT SIX PH VALUES

Author

R. BERISIO, V. S. LAMZIN, K. S. WILSON, A. ZAGARI, L. MAZZARELLA, SICA, FILOMENA, Sica, Filomena, Mazzarella, Lelio, Zagari, Adriana, Lamzin, V. S., Wilson, K. S., Berisio, R., Berisio, R, Zagari, A, R., Berisio, V. S., Lamzin, K. S., Wilson, A., Zagari, and L., Mazzarella

Abstract

The diffraction pattern of protein crystals extending to atomic resolution guarantees a very accurate picture of the molecular structure and enables the study of subtle phenomena related to protein functionality. Six structures of bovine pancreatic ribonuclease at the pH* values 5.2, 5.9, 6.3, 7.1, 8.0 and 8.8 and at resolution limits in the range 1.05-1.15A have been refined. An overall description of the six structures and several aspects, mainly regarding pH-triggered conformational changes, are described here. Since subtle variations were expected, a thorough validation assessment of the six refined models was first carried out. Some stereochemical parameters, such as the N[bond]C(alpha)[bond]C angle and the pyramidalization at the carbonyl C atoms, indicate that the standard target values and their weights typically used in refinement may need revision. A detailed comparison of the six structures has provided experimental evidence on the role of Lys41 in catalysis. Furthermore, insights are given into the structural effects related to the pH-dependent binding of a sulfate anion, which mimics the phosphate group of RNA, in the active site. Finally, the results support a number of thermodynamic and kinetic experimental data concerning the role of the disulfide bridge between Cys65 and Cys72 in the folding of RNase A.

Published
2002

133. A potential allosteric subsite generated by domain swapping in bovine seminal ribonuclease

Author

L. Vitagliano, S. Adinolfi, A. Merlino, A. ZAGARI, MAZZARELLA L., SICA, FILOMENA, Vitagliano, L, Adinolfi, S, Sica, Filomena, Merlino, Antonello, Zagari, A, Mazzarella, L., Vitagliano, L., Adinolfi, S., Merlino, A., and Zagari, A.

Subjects
Models, Molecular, domain swapping, protein-inhibitor complex, protein structure-function, X-ray diffraction, ribonuclease, Guanine, Molecular Sequence Data, protein structure-function, Electrons, Hydrogen Bonding, Ribonuclease, Pancreatic, Crystallography, X-Ray, Protein Structure, Secondary, X-ray diffraction, Kinetics, Structure-Activity Relationship, Endoribonucleases, Animals, Cattle, protein-inhibitor complex, ribonuclease, domain swapping, Crystallization, Dimerization, Allosteric Site, Dinucleoside Phosphates
Abstract

Bovine seminal ribonuclease (BS-RNase) is a peculiar member of the pancreatic-like ribonuclease superfamily endowed with unique biological functions. It has been shown that native BS-RNase is a mixture of two distinct dimeric forms. The most abundant form is characterised by the swapping of the N-terminal helix. Kinetic studies have shown that this dimer is allosterically regulated, whereas the minor component, in which no swapping occurs, exhibits typical Michaelian kinetics. In order to correlate the catalytic properties with the structural features of BS-RNase, we have determined the crystal structure of the BS-RNase swapping dimer complexed with uridylyl(2'-5')guanosine. The structure of the complex was refined to an R value of 0.189 at 1.9 A resolution. Surprisingly, the enzyme binds four dinucleotide molecules, all in a non-productive way. In the two active sites, the guanine base is located in the subsite that is specific for pyrimidines. This unusual binding has been observed also in complexes of RNase A with guanine-containing nucleotides (retro-binding). One of the two additional dinucleotide molecules bound to the enzyme is located on the surface of the protein in a pocket generated by crystal packing; the second was found in a cavity at the interface between the two subunits of the swapping dimer. There are indications that the interface site plays a role in the allosteric regulation exhibited by BS-RNase. This finding suggests that domain swapping may not merely be a mechanism that proteins adopt for the transition from a monomeric to oligomeric state but can be used to achieve modulations in catalytic function.

Published
1999

135. 'Protein Crystal Growth in the Advanced Protein Crystallisation Facility on the LMS Mission: a Comparison of Sulfolobus solfataricus Alcohol Dehydrogenase Crystals Grown on the Ground and in Microgravity'

Author

ESPOSITO L, SORRENTINO G, BERISIO R, CAROTENUTO L, GIORDANO A, RAIA C, ROSSI M, LAMZIN V. S, WILSON K. S. AND ZAGARI A., SICA, FILOMENA, Esposito, L, Sica, Filomena, Sorrentino, G, Berisio, R, Carotenuto, L, Giordano, A, Raia, C, Rossi, M, Lamzin, V. S., and Wilson, K. S. AND ZAGARI A.

Published
1998

136. Multiple b-turn conformations

Author

DEMASI, DOMENICO, CAPASSO, SANTE, FILOMENA, VITAGLIANO, LUIGI, ZAGARI, ADRIANA, SICA, FILOMENA, Demasi, Domenico, Capasso, Sante, Sica, Filomena, Filomena, Vitagliano, Luigi, Zagari, and Adriana

Published
1998

141. Deamidation of Proteins: The crystal structure of bovine pancreatic ribonuclease with an isoaspartyl residue at position 67

Author

Capasso, S., Esposito, L., Sorrentino, G., Vitagliano, L., DI DONATO, ALBERTO, SICA, FILOMENA, ZAGARI, ADRIANA, MAZZARELLA, LELIO, Capasso, S., DI DONATO, Alberto, Esposito, L., Sica, Filomena, Sorrentino, G., Vitagliano, L., Zagari, Adriana, and Mazzarella, Lelio

Subjects
Deamidation, ribonuclease A, asparagine
Abstract

The non-enzymatic deamidation of asparagine residues in proteins is a widely occurring reaction, both in vivo and in vitro. Although the importance of this process is commonly recognised, only little structural information is available on it. In order to evaluate the structural effects of this reaction in proteins, we have determined the crystal structure of a ribonuclease A derivative in which asparagine 67 has been replaced by an isoaspartyl residue, as a consequence of an in vitro deamidation reaction. The overall structure of the model, refined to a crystallographic R-factor of 0.159 at a resolution of 1.9 Å, is very similar to that of the native protein, but considerable deviations are observed in the region delimited by the disulphide bridge 65–72. In particular, the insertion of an extra methylene group in the main chain at residue 67 breaks up the hydrogen bond network that makes this region rather rigid in ribonuclease A. On the basis of the structure observed, some of the slightly but significantly different properties of this deamidated derivative, with respect to the native enzyme, can be explained.

Published
1996

150. Solid-state conformations of aminosuccinyl peptides: structure of tert-butyloxycarbonyl-L-prolyl-L-aminosuccinyl-glycyl-L-alanine methyl ester (Boc-L-Pro-L-Asu-Gly-L-Ala-OMe). A case of pseudo-translational symmetry

Author

CAPASSO SANTE, MAZZARELLA LELIO, ZAGARI ADRIANA, CASCARANO GIANLUCA, GIACOVAZZO C.A.R.M.E.L.O., SICA, FILOMENA, Capasso, Sante, Mazzarella, Lelio, Sica, Filomena, Zagari, Adriana, Cascarano, Gianluca, and Giacovazzo, C. A. R. M. E. L. O.

Subjects
X-Ray Diffraction, Protein Conformation, Molecular Sequence Data, Amino Acid Sequence, Peptides, Oligopeptides
Abstract

C20H30N4O8, M(r) = 454.48, monoclinic, P2(1), a = 13.411 (2), b = 12.592 (2), c = 14.710 (1) A, beta = 104.30 (1) degrees, V = 2407 (6) A3, Z = 4, Dx = 1.254 Mg m-3, lambda (Cu K alpha) = 1.5418 A, mu = 0.783 mm-1, F(000) = 968, room temperature, final R = 0.086, wR = 0.080 for 4055 observed reflections. The title compound is a model for the intermediate formed in the deamidation reaction of porcine adrenocorticotropin hormone. The structure presents a pseudo-translational symmetry and was solved by using a modified version of the SIR88 package. In the refinement, few stereochemical restraints were needed to handle the static disorder shown by the C-terminal fragment of one molecule in the asymmetric unit. The conformation of the two independent molecules is almost identical and is a II' beta-bend, stabilized by an intramolecular hydrogen bond. In the crystal, screw-related molecules are linked by hydrogen bonds. The two molecules in the independent unit are related by the translation vector u = 0.4962 (2)a + 0.7310 (2)b + 0.5075 (2)c.

Published
1992

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