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4 results on '"Infusini G"'

1. W-F substitutions in apomyoglobin increase the local flexibility of the N-terminal region causing amyloid aggregation: a H/D exchange study.

Author

Infusini G, Iannuzzi C, Vilasi S, Maritato R, Birolo L, Pagnozzi D, Pucci P, Irace G, and Sirangelo I

Subjects
Amyloid metabolism, Apoproteins metabolism, Deuterium Exchange Measurement, Mass Spectrometry, Mutant Proteins chemistry, Mutant Proteins metabolism, Myoglobin metabolism, Peptide Fragments metabolism, Protein Conformation, Protein Folding, Proteolysis, Amyloid chemistry, Apoproteins chemistry, Myoglobin chemistry, Peptide Fragments chemistry
Abstract

Myoglobin is an α-helical globular protein containing two highly conserved tryptophanyl residues at positions 7 and 14 in the N-terminal region. The simultaneous substitution of the two residues impairs the productive folding of the protein making the polypeptide chain highly prone to aggregate forming amyloid fibrils at physiological pH and room temperature. The role played by tryptophanyl residues in driving the productive folding process was investigated by providing structural details at low resolution of compact intermediate of three mutated apomyoglobins, i.e., W7F, W14F and the amyloid forming mutant W7FW14F. In particular, we followed the hydrogen/deuterium exchange rate of protein segments using proteolysis with pepsin followed by mass spectrometry analysis. The results revealed significant differences in the N-terminal region, consisting in an alteration of the physico-chemical properties of the 7-11 segment for W7F and in an increase of local flexibility of the 12-29 segment for W14F. In the double trypthophanyl substituted mutant, these effects are additive and impair the formation of native-like contacts and favour inter-chain interactions leading to protein aggregation and amyloid formation at physiological pH.

Published
2013
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2. Resolution of the effects induced by W → F substitutions on the conformation and dynamics of the amyloid-forming apomyoglobin mutant W7FW14F.

Author

Infusini G, Iannuzzi C, Vilasi S, Birolo L, Pagnozzi D, Pucci P, Irace G, and Sirangelo I

Subjects
Amino Acid Sequence, Animals, Apoproteins genetics, Molecular Sequence Data, Mutation, Missense, Myoglobin genetics, Phenylalanine genetics, Protein Conformation, Protein Folding, Spectrum Analysis, Tryptophan genetics, Whales, Amyloid chemistry, Apoproteins chemistry, Models, Molecular, Myoglobin chemistry, Phenylalanine chemistry, Tryptophan chemistry
Abstract

Myoglobin is an alpha-helical globular protein containing two highly conserved tryptophanyl residues at positions 7 and 14 in the N-terminal region. The simultaneous substitution of the two residues increases the susceptibility of the polypeptide chain to misfold, causing amyloid aggregation under physiological condition, i.e., neutral pH and room temperature. The role played by tryptophanyl residues in driving the folding process has been investigated by examining three mutated apomyoglobins, i.e., W7F, W14F, and the amyloid-forming mutant W7FW14F, by an integrated approach based on far-ultraviolet (UV) circular dichroism (CD) analysis, fluorescence spectroscopy, and complementary proteolysis. Particular attention has been devoted to examine the conformational and dynamic properties of the equilibrium intermediate formed at pH 4.0, since it represents the early organized structure from which the native fold originates. The results show that the W → F substitutions at position 7 and 14 differently affect the structural organization of the AGH subdomain of apomyoglobin. The combined effect of the two substitutions in the double mutant impairs the formation of native-like contacts and favors interchain interactions, leading to protein aggregation and amyloid formation.

Published
2012
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3. Resolution of the effects induced by W → F substitutions on the conformation and dynamics of the amyloid-forming apomyoglobin mutant W7FW14F

Author

Ivana Sirangelo, Silvia Vilasi, Leila Birolo, Piero Pucci, Giuseppe Infusini, Clara Iannuzzi, Gaetano Irace, Daniela Pagnozzi, Infusini, G, Iannuzzi, C, Vilasi, S, Birolo, Leila, Pagnozzi, D, Pucci, Pietro, Irace, G, Sirangelo, I., Iannuzzi, Clara, Birolo, L, Pucci, P, Irace, Gaetano, and Sirangelo, Ivana

Subjects
Models, Molecular, Amyloid, Protein Folding, Circular dichroism, Protein Conformation, Globular protein, Stereochemistry, Phenylalanine, Proteolysis, Molecular Sequence Data, Mutant, Mutation, Missense, Biophysics, Apomyoglobin, Protein aggregation, Fluorescence spectroscopy, chemistry.chemical_compound, medicine, Animals, Amino Acid Sequence, Amyloid aggregation, chemistry.chemical_classification, medicine.diagnostic_test, Myoglobin, Chemistry, Spectrum Analysis, Tryptophan, Whales, General Medicine, Protein folding, Apoproteins, Protein misfolding
Abstract

""Myoglobin is an alpha-helical globular protein containing two highly conserved tryptophanyl residues at positions 7 and 14 in the N-terminal region. The simultaneous substitution of the two residues increases the susceptibility of the polypeptide chain to misfold, causing amyloid aggregation under physiological condition, i.e., neutral pH and room temperature. The role played by tryptophanyl residues in driving the folding process has been investigated by examining three mutated apomyoglobins, i.e., W7F, W14F, and the amyloid-forming mutant W7FW14F, by an integrated approach based on far-ultraviolet (UV) circular dichroism (CD) analysis, fluorescence spectroscopy, and complementary proteolysis. Particular attention has been devoted to examine the conformational and dynamic properties of the equilibrium intermediate formed at pH 4.0, since it represents the early organized structure from which the native fold originates. The results show that the W -> F substitutions at position 7 and 14 differently affect the structural organization of the AGH subdomain of apomyoglobin. The combined effect of the two substitutions in the double mutant impairs the formation of native-like contacts and favors interchain interactions, leading to protein aggregation and amyloid formation.""

Published
2012

4. W-F Substitutions in Apomyoglobin Increase the Local Flexibility of the N-terminal Region Causing Amyloid Aggregation: A H/D Exchange Study

Author

Rosa Maritato, Silvia Vilasi, Daniela Pagnozzi, Ivana Sirangelo, Gaetano Irace, Clara Iannuzzi, Giuseppe Infusini, Leila Birolo, Piero Pucci, Infusini, G, Iannuzzi, Clara, Vilasi, S, Maritato, R, Birolo, L, Pagnozzi, D, Pucci, P, Irace, Gaetano, Sirangelo, Ivana, Iannuzzi, C, Birolo, Leila, Pucci, Pietro, Irace, G, and Sirangelo, I.

Subjects
Amyloid, Protein Folding, Protein Conformation, Globular protein, Stereochemistry, Proteolysis, Mutant, Protein aggregation, Biochemistry, Mass Spectrometry, chemistry.chemical_compound, Structural Biology, medicine, chemistry.chemical_classification, medicine.diagnostic_test, Myoglobin, Chemistry, Deuterium Exchange Measurement, General Medicine, Peptide Fragments, Folding (chemistry), Mutant Proteins, Hydrogen–deuterium exchange, Apoproteins
Abstract

Myoglobin is an α-helical globular protein containing two highly conserved tryptophanyl residues at positions 7 and 14 in the N-terminal region. The simultaneous substitution of the two residues impairs the productive folding of the protein making the polypeptide chain highly prone to aggregate forming amyloid fibrils at physiological pH and room temperature. The role played by tryptophanyl residues in driving the productive folding process was investigated by providing structural details at low resolution of compact intermediate of three mutated apomyoglobins, i.e., W7F, W14F and the amyloid forming mutant W7FW14F. In particular, we followed the hydrogen/deuterium exchange rate of protein segments using proteolysis with pepsin followed by mass spectrometry analysis. The results revealed significant differences in the N-terminal region, consisting in an alteration of the physico-chemical properties of the 7-11 segment for W7F and in an increase of local flexibility of the12-29 segment for W14F. In the double trypthophanyl substituted mutant, these effects are additive and impair the formation of native-like contacts and favour inter-chain interactions leading to protein aggregation and amyloid formation at physiological pH.

Published
2013

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