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9 results on '"Degioia L"'

5. Ni-Fe hydrogenases: A density functional theory study of active site models.

Author

DeGioia, L. and Fantucci, P.

Subjects
*HYDROGENASE, *NICKEL compounds, *IRON compounds, *ENZYMES, *BIOCHEMICAL mechanism of action
Abstract

Investigates the possible intermediates in the mechanism of dihydrogen activation by the nickel-iron center of nickel-iron hydrogenases using quantum chemical methods. Structural and electronic properties of the active site models; Spectroscopical identification of the enzymes; Redox chemistry of the hydrogenases; Role of the cysteine ligands in the reactions.

Published
1999
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7. Cloning and characterization of a new isoform of the interleukin 1 receptor antagonist

Author

Francesco Colotta, Nadia Polentarutti, Marta Muzio, Marina Sironi, Alberto Mantovani, Martino Introna, Guido Poli, L. De Gioia, Muzio, M, Polentarutti, N, Sironi, M, Poli, Guido, Degioia, L, Introna, M, Mantovani, A, and Colotta, F.

Subjects
Sialoglycoproteins, Immunology, Molecular Sequence Data, Biology, Transfection, Exon, Complementary DNA, Immunology and Allergy, Humans, Amino Acid Sequence, Cloning, Molecular, Peptide sequence, Gene, DNA Primers, Messenger RNA, COS cells, Base Sequence, Alternative splicing, Receptors, Interleukin-1, Exons, Articles, Molecular biology, Reverse transcriptase, Alternative Splicing, Interleukin 1 Receptor Antagonist Protein, Biochemistry, Genes, Interleukin-1
Abstract

By reverse transcriptase polymerase chain reaction on messenger RNA from human polymorphonuclear cells, we have isolated a sequence identical to the cDNA coding for intracellular interleukin 1 receptor antagonist (icIL-1ra), but containing an additional in-frame 63-bp sequence located three codons downstream of the translation start of icIL-1ra. This additional sequence is inserted between the first and second exon of the intracellular form, the latter of which is colinear with part of the first exon of the secreted form of IL-1ra. The additional sequence is coded by an extra exon located 2 kb downstream the first icIL-1ra-specific exon. The complementary DNA sequence of the alternatively spliced form of icIL-1ra shows that the predicted protein differs from classical icIL-1ra in the NH2 terminus by insertion of a leaderless sequence of 21 amino acids rich in glycine and glutamic acid residues. Transcripts coding for this new form of icIL-1ra were detected in activated fibroblasts, keratinocytes, and at low levels in myelomonocytic cells. The recombinant protein expressed in COS cells had an apparent molecular mass in sodium dodecyl sulfate polyacrylamide gel electrophoresis of 25 kD compared to 22 kD of classical icIL-1ra, and was mostly intracellular. The ability of this new form of icIL-1ra to inhibit IL-1 activity, in terms of induction of E-selectin and human immunodeficiency virus replication, was comparable to that of classical icIL-1ra. We propose to refer to this new form of icIL-1ra as icIL-1ra type II.

Published
1995

8. Regulation of hSos1 activity is a system-level property generated by its multi-domain structure.

Author

Sacco E, Farina M, Greco C, Lamperti S, Busti S, Degioia L, Alberghina L, Liberati D, and Vanoni M

Subjects
Computational Biology, Gene Knockout Techniques, Genetic Complementation Test, Humans, Models, Genetic, Models, Molecular, Monte Carlo Method, Protein Interaction Domains and Motifs, Protein Structure, Tertiary, SOS1 Protein genetics, Saccharomyces cerevisiae genetics, Signal Transduction, Structure-Activity Relationship, Two-Hybrid System Techniques, ras Guanine Nucleotide Exchange Factors genetics, ras Guanine Nucleotide Exchange Factors metabolism, SOS1 Protein chemistry, SOS1 Protein metabolism
Abstract

The multi-domain protein hSos1 plays a major role in cell growth and differentiation through its Ras-specific guanine nucleotide exchange domain whose complex regulation involves intra-molecular, inter-domain rearrangements. We present a stochastic mathematical model describing intra-molecular regulation of hSos1 activity. The population macroscopic effect is reproduced through a Monte-Carlo approach. Key model parameters have been experimentally determined by BIAcore analysis. Complementation experiments of a Saccharomyces cerevisiae cdc25(ts) strain with Sos deletion mutants provided a comprehensive data set for estimation of unknown parameters and model validation. The model is robust against parameter alteration and describes both the behavior of Sos deletion mutants and modulation of activity of the full length molecule under physiological conditions. By incorporating the calculated effect of amino acid changes at an inter-domain interface, the behavior of a mutant correlating with a developmental syndrome could be simulated, further validating the model. The activation state of Ras-specific guanine nucleotide exchange domain of hSos1 arises as an "emergent property" of its multi-domain structure that allows multi-level integration of a complex network of intra- and inter-molecular signals., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Published
2012
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9. Mutations in the "lid" region affect chain length specificity and thermostability of a Pseudomonas fragi lipase.

Author

Santarossa G, Lafranconi PG, Alquati C, DeGioia L, Alberghina L, Fantucci P, and Lotti M

Subjects
Amino Acid Sequence, Amino Acid Substitution, Binding Sites, Caprylates metabolism, Enzyme Stability, Hydrolysis, Kinetics, Lipase genetics, Models, Molecular, Molecular Sequence Data, Protein Structure, Tertiary, Pseudomonas fragi genetics, Sequence Alignment, Substrate Specificity, Temperature, Triglycerides metabolism, Lipase chemistry, Lipase metabolism, Mutation genetics, Protein Denaturation, Pseudomonas fragi enzymology
Abstract

The cold-adapted Pseudomonas fragi lipase (PFL) displays highest activity on short-chain triglyceride substrates and is rapidly inactivated at moderate temperature. Sequence and structure comparison with homologous lipases endowed with different substrate specificity and stability, pointed to three polar residues in the lid region, that were replaced with the amino acids conserved at equivalent positions in the reference lipases. Substitutions at residues T137 and T138 modified the lipase chain-length preference profile, increasing the relative activity towards C8 substrates. Moreover, mutations conferred to PFL higher temperature stability. On the other hand, replacement of the serine at position 141 by glycine destabilized the protein.

Published
2005
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