Fac-simile Scheda Linee di Ricerca - Federalimentare

3. Rasmussen P, Barbiroli A, Bonomi F, Faoro F, Ferranti P, Iriti M, Picariello G, Iametti S.Formation of structured polymers upon controlled denaturation of beta-lactoglobulin with differentchaotropes. Biopolymers 86:57-72, 2007Prolonged exposure (>90 days) of bovine beta-lactoglobulin (BLG) to subdenaturing concentrations of eitherurea or potassium thiocyanate resulted in the formation of ordered polymers in the form of fibrils. The fibrils obtainedwith each chaotrope showed major differences in morphology, surface properties, thiol accessibility, andstability to dissociating agents as a consequence of the different chemical bonds involved in their stabilization.Hydrophobic interactions between BLG monomers are predominant in thiocyanate-formed fibrils, whereas ureaformedfibrils are stabilized by intermolecular disulfides generated through a thiol-disulfide exchange reaction.The different features of fibrils obtained with each chaotrope relate to the peculiar structural features and chemicalproperties of the "active" monomers generated by subdenaturing chaotrope concentrations in the early phasesof the polymerization process, as detected by spectroscopic and limited proteolysis/mass spectrometry studies inthe earliest stages of the action of individual chaotropes. The chaotrope-specific features of these early intermediatesin turn affect the polymerization mechanism, whose intermediates were studied by size-exclusion chromatographyon the soluble fraction at different times of fibril formation. The potential of these findings for the productionof protein-derived nanostructures having different and controlled geometries and chemical properties isalso discussed.4. Picariello G, Ferranti P, Mamone G, Roepstorff P, Addeo F. Identification of N-linked glycoproteinsin human milk by hydrophilic interaction liquid chromatography and mass spectrometry.Proteomics 8:3833-3847, 2008 (IF international journal)Breastfeeding is now generally recognized as a critical factor in protecting newborns against infections. Animportant mechanism responsible for the antibacterial and antiviral effects of breast milk is the prevention ofpathogen adhesion to host cell membranes mediated by a number of glycoconjugates, also includingglycoproteins. A number of approaches to describe the complexity of human milk proteome have provided onlya partial characterization of restricted classes of N-linked glycoproteins. To achieve this objective, profiling N-linked glycoproteins of human milk was performed by Hydrophilic Interaction LC (HILIC) and MS analysis.Glycopeptides were selectively enriched from the protein tryptic digest of human milk samples.Oligosaccharide-free peptides obtained by peptide N-glycosidase F (PNGase F) treatment were characterized bya shotgun MS-based approach, allowing the identification of N-glycosylated sites localized on proteins. Usingthis strategy, 32 different glycoproteins were identified and 63 N-glycosylated sites encrypted in them werelocated. The glycoproteins include immunocompetent factors, membrane fat globule-associated proteins,enzymes involved in lipid degradation and cell differentiation, specific receptors, and other gene products withstill unknown functions.SISTAL - SOCIETA’ ITALIANA DI SCIENZE E TECNOLOGIE ALIMENTARIDipartimento di Scienze e Tecnologie Agroalimentari, Università degli Studi della TusciaVia San Camillo de Lellis, 01100 ViterboTel.: 0761- 35 74 94/7 , Fax: 0761- 35 74 98, e-mail: mmoresi@unitus.it288