Biochemistry and Molecular Biophysics. Coordinator: Venturoli

The research group has the mission to understand solvent-protein interaction at the molecular detail, elucidate the relationship between protein function and conformational dynamics in photosynthetic proteins, and characterize sugar- and protein-based glassy matrices acting as protein preservation media

Research themes

The relationship between conformational dynamics and function in photo-excitable proteins

The internal dynamics of proteins, tightly coupled to solvent dynamics, is extremely complex, including highly non harmonic components, which are intimately connected to protein function. Our studies are aimed to clarify the relationship between protein dynamics and function, by using photo-excitable proteins which allow time-resolved spectroscopic approaches. The examined model proteins are the bacterial photosynthetic reaction center, photosystem I and II, and bacterial photoreceptors (belonging to the LOV protein family). The incorporation into disaccharide glassy matrices of variable hydration allows to modulate the internal dynamics of protein complexes, and to examine at room temperature the effects on the rate of photo-induced electron transfer (in photosynthetic complexes) or the inter-conversion between different states of the photo-cycle (in photoreceptors). To this end, time-resolved laser absorption spectroscopy in the visible and near IR is used in our laboratory. FTIR spectroscopy provides in parallel information on the structural and dynamical coupling between the protein and the solvent.

Bioprotection mechanisms in dehydrated glassy matrices

The embedding of biomolecules, in particular proteins, into dehydrated glassy matrices formed by the disaccharides trehalose and sucrose causes a drastic inhibition of the biomolecule conformational dynamics, resulting in an extraordinary thermal stability. This behaviour is the basis of the natural phenomenon of anhydrobiosis and of a number of pharmaceutical and biotechnological applications. Our group, in collaboration with L. Cordone (Department of Physics and Astronomy, University of Palermo), has formulated a molecular model for bioprotection (anchorage hypothesis), which brings back the dynamical protein-matrix coupling to the formation of extended H-bond networks, involving surface groups of the embedded protein, residual water molecules and the sugar. In order to test the model and better define its molecular details, we are characterizing the structure and dynamics of amorphous matrices consisting of model proteins and disaccharides (or other cosolutes synthesized under stress conditions by anhydrobiotic organisms) by using static and time-resolved FTIR and high-resolution (W-band) EPR spectroscopy. The latter studies are performed in collaboration with the Max-Planck-Institut für Chemische Energiekonversion in Muelheim. Recently these studies have been extended to the characterization of the bioprotective properties of dehydrated matrices formed by intrinsically disordered proteins (CAHS and LEA), purified from anhydrobiotic organisms.

Lab members

Giovanni Venturoli (visit the institutional personal website)

Francesco Francia (visit the institutional personal website)

Internship projects

Internship pojects focused on the research themes summarized above are available for First cycle degree (Corso di Laurea in Scienze Biologiche, Corso di laurea in Biotecnologia) and Second cycle degree (Corso di laurea Magistrale in Biologia Molecolare e Cellulare, Biotecnologie Molecolari e Industriali, Fotochimica e Materiali Molecolari)

Main publications

Francia, F., Khalfaoui-Hassani, B., Lanciano, P., Musiani, F., Noodleman, L., Venturoli, G. and Daldal, F. (2019) “The cytochrome b lysine 329 residue is critical for ubihydroquinone oxidation and proton release at the Qo site of bacterial cytochrome bc1” Biochim. Biophys. Acta – Bioenergetics 1860: 167-179. http://pubs.acs.org/doi/abs/10.1021/acs.jpclett.6b02449

Malferrari, M., Savitsky, A., Lubitz, W., Möbius, K. and Venturoli, G. (2016). “Protein immobilization capabilities of sucrose and trehalose glasses: the effect of protein/sugar concentration unraveled by high-field EPR.” J. Phys. Chem. Lett. 7: 4871-4877. http://pubs.acs.org/doi/abs/10.1021/acs.jpclett.6b02449

Malferrari, M., Francia, F. and Venturoli, G. (2015). “Retardation of protein dynamics by trehalose in dehydrated systems of photosynthetic reaction centers. Insights from electron transfer and thermal denaturation kinetics.” J. Phys. Chem. B 119: 13600-13618. http://pubs.acs.org/doi/10.1021/acs.jpcb.5b02986

Selva, C., Malferrari, M., Ballardini, R., Ventola, A., Francia, F. and Venturoli, G. (2013). “Trehalose preserves the integrity of lyophilized phycoerithrin-antihuman CD8 antibody conjugates and enhances their thermal stability in flow cytometric assays.” J. Pharm. Sci. 102: 649-659. . http://dx.doi.org/10.1002/jps.23398

Francia, F., Dezi, M., Mallardi, A., Palazzo, G., Cordone, L. and Venturoli, G. (2008) “Protein-matrix coupling/uncoupling in “dry” systems of photosynthetic reaction center embedded in trehalose/sucrose: the origin of trehalose peculiarity.” J. Am. Chem. Soc. 130: 10240-10246. http://pubs.acs.org/doi/abs/10.1021/ja801801p

Contacts