title: Functional and dysfunctional conformers of human neuroserpin characterized by optical spectroscopies and Molecular Dynamics.
abstract: Neuroserpin (NS) is a serine protease inhibitor (SERPIN) involved in different neurological pathologies, including the Familial Encephalopathy with Neuroserpin Inclusion Bodies (FENIB), related to the aberrant polymerization of NS mutants. Here we present an in vitro and in silico characterization of native neuroserpin and its dysfunctional conformation isoforms: the proteolytically cleaved conformer, the inactive latent conformer, and the polymeric species. Based on circular dichroism and fluorescence spectroscopy, we present an experimental validation of the latent model and highlight the main structural features of the different conformers. In particular, emission spectra of aromatic residues yield distinct conformational fingerprints, that provide a novel and simple spectroscopic tool for selecting serpin conformers in vitro. Based on the structural relationship between cleaved and latent serpins, we propose a structural model for latent NS, for which an experimental crystallographic structure is lacking. Molecular Dynamics simulations suggest that NS conformational stability and flexibility arise from a spatial distribution of intramolecular salt-bridges and hydrogen bonds.
authors.affiliation: Institute of Biophysics, National Research Council of Italy, Palermo, Italy.
authors.forename: Rosina
authors.initials: R
authors.lastname: Noto
authors.affiliation: Institute of Biophysics, National Research Council of Italy, Palermo, Italy.
authors.forename: Maria Grazia
authors.initials: MG
authors.lastname: Santangelo
authors.affiliation: Department of Physics and Chemistry, University of Palermo, Palermo, Italy.
authors.forename: Matteo
authors.initials: M
authors.lastname: Levantino
authors.affiliation: Department of Physics and Chemistry, University of Palermo, Palermo, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Cupane
authors.affiliation: Institute of Biophysics, National Research Council of Italy, Palermo, Italy.
authors.forename: Maria Rosalia
authors.initials: MR
authors.lastname: Mangione
authors.affiliation: Institute of Biophysics, National Research Council of Italy, Palermo, Italy; Department of Biosciences, Institute of Biophysics CNR, Italy and CIMAINA, University of Milano, Milan, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Parisi
authors.affiliation: Department of Biosciences, Institute of Biophysics CNR, Italy and CIMAINA, University of Milano, Milan, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Ricagno
authors.affiliation: Department of Biosciences, Institute of Biophysics CNR, Italy and CIMAINA, University of Milano, Milan, Italy.
authors.forename: Martino
authors.initials: M
authors.lastname: Bolognesi
authors.affiliation: Institute of Biophysics, National Research Council of Italy, Palermo, Italy. Electronic address: mauro.manno@cnr.it.
authors.forename: Mauro
authors.initials: M
authors.lastname: Manno
authors.affiliation: Institute of Biophysics, National Research Council of Italy, Palermo, Italy.
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Martorana
mesh_terms: D002942:Circular Dichroism; D004831:Epilepsies, Myoclonic / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D020271:Heredodegenerative Disorders, Nervous System / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D006860:Hydrogen Bonding; D056004:Molecular Dynamics Simulation; D009479:Neuropeptides / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation; D017510:Protein Folding; D020033:Protein Isoforms / Q000737:chemistry / Q000235:genetics; D017433:Protein Structure, Secondary; D015842:Serine Proteinase Inhibitors / Q000737:chemistry* / Q000378:metabolism; D015843:Serpins / Q000737:chemistry* / Q000378:metabolism; D000097522:Neuroserpin
chemical_list: D009479:Neuropeptides; D020033:Protein Isoforms; D015842:Serine Proteinase Inhibitors; D015843:Serpins; D000097522:Neuroserpin
keywords: Circular dichroism; Conformational disease; Fluorescence; Molecular Dynamics; Neuroserpin; Serpin