Protein Crowding Effects on Hydration Water Dynamics

Year: 2025

Authors: Caminiti L., Taddei M., Catalini S., Bartolini P., Taschin A., Torre R.

Autors Affiliation: Univ Firenze, Dipartimento Fis Astron, I-50019 Sesto Fiorentino, FI, Italy; European Lab Nonlinear Spect, I-50019 Sesto Fiorentino, FI, Italy; Univ Perugia, Dipartimento Fis & Geol, I-06123 Perugia, PG, Italy; CNR, Ist Nazl Ott, I-50019 Sesto Fiorentino, FI, Italy.

Abstract: We propose a time-resolved optical Kerr effect study of the structural and vibrational dynamics of the hydration water surrounding the lysozyme on a very fast time scale. Measurements as a function of lysozyme concentration make it possible to distinguish the hydration water contribution from that of both the bulk water and the protein. Our results provide experimental evidence of the existence of two structural dynamics of hydration water, associated with a hydrogen bond exchange relaxation process and with the reorganization of water molecules induced by protein structural fluctuations. Likewise, we evaluated the vibrational dynamics of the water hydration layer at subpicosecond time scales. Our measurements of hydration water properties reveal the presence of a crossover point at a specific protein concentration. This crossover marks the transition between two clustering regimes with distinct hydration characteristics and establishes a possible threshold for protein crowding.

Journal/Review: JOURNAL OF PHYSICAL CHEMISTRY LETTERS

Volume: 16 (9)      Pages from: 2340  to: 2347

More Information: This research was funded by Ministero dell’Istruzione dell’Universita e della Ricerca Italiano (PRIN-2022JWAF7Y), Project CNR-FOE-LENS-2023; European Union’s Horizon 2020 research and innovation program under Grant Agreement 871124 Laserlab-Europe; and the European Union’s NextGenerationEU Programme with the I-PHOQS Infrastructure (IR0000016, ID D2B8D520, CUP B53C22001750006). 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 23-G-15445-3.
KeyWords: Liquid-phase-separation; Lysozyme Solutions
DOI: 10.1021/acs.jpclett.4c03391