Michele Stofella - Academia.edu (original) (raw)

Papers by Michele Stofella

The purpose of this work is to provide computational methods to fingerprint protein dynamics prob... more The purpose of this work is to provide computational methods to fingerprint protein dynamics probed by hydrogen deuterium exchange mass spectroscopy (HDX-MS). Hydrogen deuterium exchange consists in the spontaneous exchange of amide hydrogens of amino acids with deuterium contained in solution. The consequent increase in mass of the protein can be monitored by mass spectroscopy. Moreover, the exchange rate (or protection factor) provides a parameter probing protein dynamics at single residue resolution. The ExPfact algorithm is a computational method implemented to extract fine-grained information out of coarse-grained HDX-MS experimental data. The method is validated through a comparison with protection factors estimated from HDX-NMR measurements probing the mouse prion protein. Also, a second application studying glycogen phosphorylase shows how structural changes between different states of the same protein can be detected at amino acidic resolution. Furthermore, fine-grained inf...

Experimental measurement of time-dependent spontaneous exchange of amide protons with deuterium o... more Experimental measurement of time-dependent spontaneous exchange of amide protons with deuterium of the solvent provides information on the structure and dynamical structural variation in proteins. Two experimental techniques are used to probe the exchange: NMR, which relies on different magnetic properties of hydrogen and deuterium, and MS, which exploits the change in mass due to deuteration. NMR provides residue-specific information, that is, the rate of exchange or, analogously, the protection factor (i.e., the unitless ratio between the rate of exchange for a completely unstructured state and the observed rate). MS provides information that is specific to peptides obtained by proteolytic digestion. The spatial resolution of HDX-MS measurements depends on the proteolytic pattern of the protein, the fragmentation method used, and the overlap between peptides. Different computational approaches have been proposed to extract residue-specific information from peptide-level HDX-MS measurements. Here, we demonstrate the advantages of a method recently proposed that exploits self-consistency and classifies the possible sets of protection factors into a finite number of alternative solutions compatible with experimental data. The degeneracy of the solutions can be reduced (or completely removed) by exploiting the additional information encoded in the shape of the isotopic envelopes. We show how sparse and noisy MS data can provide high-resolution protection factors that correlate with NMR measurements probing the same protein under the same conditions.

Molecular & Cellular Proteomics, 2021

Neurodegenerative diseases are characterized by the abnormal accumulation of aggregated proteins ... more Neurodegenerative diseases are characterized by the abnormal accumulation of aggregated proteins in the brain. Using in vivo pulse isotope labeling, we screened the proteome for changes in protein turnover and abundance in multiple mouse models of neurodegeneration. These data suggest that the disease state of pathologically affected tissue is characterized by a proteome-wide increase in protein turnover and repair. In contrast, in healthy wild-type mice, aging in the mammalian brain is associated with a global slowdown in protein turnover. Highlights • Multidimensional proteomic screen to detect imbalances in mouse models of disease. • Increased proteome turnover in multiple symptomatic neurodegeneration mouse models. • Healthy aging is associated with a global decrease in protein turnover.

Biochimica et Biophysica Acta (BBA) - General Subjects, 2020

including the URL of the record and the reason for the withdrawal request. BBA Advances in Comput... more including the URL of the record and the reason for the withdrawal request. BBA Advances in Computational Molecular Biophysics.

The purpose of this work is to provide computational methods to fingerprint protein dynamics prob... more The purpose of this work is to provide computational methods to fingerprint protein dynamics probed by hydrogen deuterium exchange mass spectroscopy (HDX-MS). Hydrogen deuterium exchange consists in the spontaneous exchange of amide hydrogens of amino acids with deuterium contained in solution. The consequent increase in mass of the protein can be monitored by mass spectroscopy. Moreover, the exchange rate (or protection factor) provides a parameter probing protein dynamics at single residue resolution. The ExPfact algorithm is a computational method implemented to extract fine-grained information out of coarse-grained HDX-MS experimental data. The method is validated through a comparison with protection factors estimated from HDX-NMR measurements probing the mouse prion protein. Also, a second application studying glycogen phosphorylase shows how structural changes between different states of the same protein can be detected at amino acidic resolution. Furthermore, fine-grained inf...

Experimental measurement of time-dependent spontaneous exchange of amide protons with deuterium o... more Experimental measurement of time-dependent spontaneous exchange of amide protons with deuterium of the solvent provides information on the structure and dynamical structural variation in proteins. Two experimental techniques are used to probe the exchange: NMR, which relies on different magnetic properties of hydrogen and deuterium, and MS, which exploits the change in mass due to deuteration. NMR provides residue-specific information, that is, the rate of exchange or, analogously, the protection factor (i.e., the unitless ratio between the rate of exchange for a completely unstructured state and the observed rate). MS provides information that is specific to peptides obtained by proteolytic digestion. The spatial resolution of HDX-MS measurements depends on the proteolytic pattern of the protein, the fragmentation method used, and the overlap between peptides. Different computational approaches have been proposed to extract residue-specific information from peptide-level HDX-MS measurements. Here, we demonstrate the advantages of a method recently proposed that exploits self-consistency and classifies the possible sets of protection factors into a finite number of alternative solutions compatible with experimental data. The degeneracy of the solutions can be reduced (or completely removed) by exploiting the additional information encoded in the shape of the isotopic envelopes. We show how sparse and noisy MS data can provide high-resolution protection factors that correlate with NMR measurements probing the same protein under the same conditions.

Molecular & Cellular Proteomics, 2021

Neurodegenerative diseases are characterized by the abnormal accumulation of aggregated proteins ... more Neurodegenerative diseases are characterized by the abnormal accumulation of aggregated proteins in the brain. Using in vivo pulse isotope labeling, we screened the proteome for changes in protein turnover and abundance in multiple mouse models of neurodegeneration. These data suggest that the disease state of pathologically affected tissue is characterized by a proteome-wide increase in protein turnover and repair. In contrast, in healthy wild-type mice, aging in the mammalian brain is associated with a global slowdown in protein turnover. Highlights • Multidimensional proteomic screen to detect imbalances in mouse models of disease. • Increased proteome turnover in multiple symptomatic neurodegeneration mouse models. • Healthy aging is associated with a global decrease in protein turnover.

Biochimica et Biophysica Acta (BBA) - General Subjects, 2020

including the URL of the record and the reason for the withdrawal request. BBA Advances in Comput... more including the URL of the record and the reason for the withdrawal request. BBA Advances in Computational Molecular Biophysics.