Bachelor’s degree: Chemistry
Master’s degree: Chemical Sciences
Structure and Function Investigation on Membrane-Binding Proteins: a Neutron Reflectometry Study
This PhD project has been focused on investigating the interaction of proteins with model mem-branes, in the form of both mono- and bilayers. Two different sets of protein have been studied: (i) proteins from Clathrin-mediated endocytosis and (ii) peptides from SARS-CoV-2 Spike protein.
(i) Clathrin-mediated endocytosis is the main mechanism by which eukaryotic cells internalize and recycle most membrane proteins and is driven by different Adaptor and Modulator Proteins, which solely interact with the inner leaflet of the cell membrane. By exploiting techniques such as ellip-sometry, pressure–area isotherms and Neutron Reflectometry, the aim of this work has been to in-vestigate the binding and resultant structures formed by the adaptor protein CALM and by the modulator FCHo2 on association with lipid monolayers enriched in either phosphatidyl-inositol-4,5-diphosphate (PIP2), or 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-L-serine (POPS). In particu-lar, Neutron Reflectometry allowed us to determine the position and orientation of both CALM and FCHo2 with respect to the membrane.
(ii) The well-known SARS-CoV-2, which is responsible for a lethal respiratory illness since its out-break at the end of 2019, is an encapsulated virus. Indeed it has a lipid envelope with membrane proteins, such as Spike protein, responsible of receptor recognition. The fusion domain of the Spike, which can be divided in four Fusion Peptides (FP), is responsible for triggering the fusion between viral and host membranes, which is the critical stage of the infection. The aim of the pro-ject has been to investigate the role of the different FP in the fusion process, also exploring the in-fluence of Calcium. In particular, Neutron Reflectometry shed light on the critical role of FP1 (i.e. the N-terminal of the Spike fusion domain), which is able to fully penetrate membranes in a Calci-um dependent manner