Biochemistry and Molecular Biophysics. Coordinator: Francia

Research topics

1.  Preservation of biological macromolecules. Agents capable of maintaining the structural and functional properties of proteins (enzymes, hormones, and antibodies) are and will continue to be increasingly sought after, given the rapid growth of protein-based drugs produced by the pharmaceutical industry. Disaccharides have long been known to be effective stabilizers of biological macromolecules subjected to freeze-drying processes. Among these, trehalose, a disaccharide composed of two glucose units joined by an α-α 1-1 glycosidic bond, has proven particularly effective in many cases, but the mechanism by which this disaccharide stabilizes macromolecules remains widely debated. The main aim of this line of research is to understand whether, under dehydration conditions in the presence of trehalose, proteins maintain a layer of surface water (in agreement with the water entrapment hypothesis) or whether this water is lost and replaced by trehalose (in agreement with the water replacement hypothesis). Analysis of dehydrated protein-disaccharide matrices by infrared (IR) or near-infrared (NIR) spectroscopy is particularly informative and can be used to assess the residual water content in disaccharide-protein matrices equilibrated at different relative humidities. Furthermore, analysis of spectra in the infrared absorption range 1900-2300 cm^-1 allows observation of the water association band. This band is composed of different contributions due to differences in the type of hydrogen bonds formed by water. Deconvolution of the association band allows the different contributions to be assigned to different water subpopulations, depending on whether the interaction is with the protein surface or the trehalose matrix.

2.  Use of chromatophores to study the effect of ionic liquids on membrane potential.This line of research aims to study the interactions between ionic liquids (ILs) and bioenergetically active membranes, using chromatophores as a model. Chromatophores are closed membrane vesicles, isolated from photosynthetic bacteria, which present all the functional elements of the electron transport chain in their native conformation. The effect of ILs on the electrochemical potential of chromatophores is observable through photoactivation of the photosynthetic apparatus, by monitoring the change in absorbance of carotenoids associated with antenna complex II over time. The absorption spectrum of these carotenoids responds linearly to the intramembrane electric field generated by the charge separation that occurs in the Photosynthetic Reaction Center after its photooxidation, providing information on the dissipation of the electrical component of the membrane electrochemical potential (ΔΨ). Experimental traces of the electric field decay are analyzed using a model derived from experiments involving the interactions between hydrophobic ions and artificial lipid bilayers, and allow a thorough understanding of the interaction that determines the ILs-induced effects on the cell membrane.

Lab Members

Francesco Francia,  Associate Professor 

Giovanni Venturoli,  Alma Mater Professor 

Corrado Selva, PhD Student

Internship projects

An internship is available for bachelor's degree students and an internship for master's or single-cycle degree students, from February to October each year. The topics will be discussed with interested students.

Main publications

• - Francia F, Dezi M, Mallardi A, Palazzo G, Cordone L, 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.  130:10240-6. http://dx.doi.org/10.1021/ja801801p

  - Savitsky A, Malferrari M, Francia F, Venturoli G, Möbius K. (2010) “Bacterial photosynthetic reaction centers in trehalose glasses: coupling between protein conformational dynamics and electron-transfer kinetics as studied by laser-flash and high-field EPR spectroscopies.” J Phys Chem B.  114:12729-43.       http://dx.doi.org/10.1021/jp105801q

  - Selva C, Malferrari M, Ballardini R, Ventola A, Francia F, Venturoli G. (2013) “Trehalose preserves the integrity of lyophilized phycoerythrin-antihuman CD8 antibody conjugates and enhances their thermal stability in flow cytometric assays.” J Pharm Sci. 102(2):649-59. http://dx.doi.org/10.1002/jps.23398ù

   - Venturoli G, Mamedov MD, Vitukhnovskaya LA, Semenov AY, Francia F. (2025) “Trehalose Interferes with the Photosynthetic Electron Transfer Chain of Cereibacter (Rhodobacter) sphaeroides Permeating the Bacterial Chromatophore Membrane.” Int J Mol Sci. 25, 13420.  http://dx.doi.org/10.3390/ijms252413420

  - Bin T, Venturoli G, Ghelli AM, Francia F. (2024) “Use of bacterial photosynthetic vesicles to evaluate the effect of ionic liquids on the permeability of biological membranes.” Biochim Biophys Acta Biomembr. 1866:184291.   http://dx.doi.org/10.1016/j.bbamem.2024.184291