Amyloidogenic and non-amyloidogenic molten globule conformation of ?-lactoglobulin in self-crowded regime

Year: 2023

Authors: Venturi S., Rossi B., Tortora M., Torre R., Lapini A., Foggi P., Paolantoni M., Catalini S.

Autors Affiliation: Univ Firenze, European Lab Nonlinear Spect, Via Nello Carrara 1, I-50019 Sesto Fiorentino, Italy; Elettra Sincrotrone Trieste, SS 114 km 163-5, I-34149 Trieste, Italy; AREA Sci Pk, Padriciano 99, I-34149 Trieste, Italy; Univ Firenze, Dipartimento Fis Astron, Via G Sansone 1, I-50019 Sesto Fiorentino, Italy; Univ Parma, Dipartimento Sci Chim Vita & Sostenibilit Ambient, Parco Area Sci 17-A, I-43124 Parma, Italy; Univ Perugia, Dipartimento Chim Biol & Biotecnol, Via Elce sotto 8, I-06123 Perugia, Italy; Ist Nazl Ottica, CNR INO, Consiglio Nazl Ric, Largo Fermi 6, I-50125 Florence, Italy; Univ Perugia, Dipartimento Fis & Geol, Via Pascoli, I-06123 Perugia, Italy.

Abstract: Molecular insights on the beta-lactoglobulin thermal unfolding and aggregation are derived from FTIR and UV Resonance Raman (UVRR) investigations. We propose an in situ and in real-time approach that thanks to the identification of specific spectroscopic markers can distinguish the two different unfolding pathways pursued by beta-lactoglobulin during the conformational transition from the folded to the molten globule state, as triggered by the pH conditions. For both the investigated pH values (1.4 and 7.5) the greatest conformational variation of beta-lactoglobulin occurs at 80 degrees C and a high degree of structural reversibility after cooling is observed. In acidic condition beta-lactoglobulin exposes to the solvent its hydrophobic moieties in a much higher extent than in neutral solution, resulting on a highly open conformation. Moving from the diluted to the self-crowded regime, the solution pH and consequently the different molten globule conformation select the amyloid or non-amyloid aggregation pathway. At acidic condition the amyloid aggregates form during the heating cycle leading to the formation of transparent hydrogel. On the contrary, in neutral condition the amyloid aggregates never form. Information on the secondary structure conformational change of beta-lactoglobulin and the formation of amyloid aggregates are obtained by FTIR spectroscopy and are related to the information of the structural changes localized around the aromatic amino acid sites by UVRR technique. Our results highlight a strong involvement of the chain portions where tryptophan is located on the formation of amyloid aggregates.

Journal/Review: INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES

Volume: 242      Pages from: 124621-1  to: 124621-9

More Information: The authors acknowledge Elettra Sincrotrone Trieste for providing access to its synchrotron radiation facilities and for financial support (proposal number 20205486). The authors gratefully acknowledge A. Gessini for the technical support during the UVRR measurements at IUVS beamline of the Elettra Sincrotrone Trieste. A great acknowledgment event to European Union’s Horizon 2020 research, the innovation program under grant agreement no 871124 Laserlab-Europe and Ministero dell’Istruzione dell’Universita e della Ricerca Italiano, PRIN2017-2017Z55KCW for the financial support. MT thanks the European Regional Development Fund and Interreg V-A Italy Austria 2014-2020 through the Interreg Italy-Austria project ITAT 1059 InCIMa4 InCIMa for Science and SMEs. S.C. thanks the research project FSE-REACT EU financed by National Social Fund-National Operative Research Program and Innovation 2014-2020 (D.M. 1062/2021), personal Grant number 23-G-15445-3. MP acknowledges Universita degli Studi di Perugia and MUR for support within the project Vitality.
KeyWords: beta-Lactoglobulin; Amyloid-aggregates; Self-crowding; UVRR; FTIR
DOI: 10.1016/j.ijbiomac.2023.124621

ImpactFactor: 7.700
Citations: 4
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