Characterisation of the Hepatitis C Virus protein NS5A interaction with human SH3 domains

The hepatitis C virus protein NS5A has various functions in different stages of the viral life cycle. It has the ability to interact with a great body of proteins including viral and human proteins. NS5A binds to a set of human Src homology 3 domains (SH3). Three polyproline motifs (PxxP) on NS5A, which are canonical binding sites for SH3 domains are supposed to be crucial for this event. The Bridging integrator 1 (Bin1) plays a key role in inducing actively membrane curvature via its Bin–amphiphysin–Rvs (BAR) domain. In the past years, the tumour suppressor role of Bin1 in controlling Myc activity moved more and more in the focus of research, regarding Myc`s importance in apoptotic signalling pathways. There is clear evidence that the Bin1-Myc-interaction is mediated through the SH3 domain of Bin1. Aim of this work is the characterisation of the NS5A interaction with certain SH3 domains and the understanding discrimination determinants for the binding interface of its promiscuous interaction with SH3 domains. Therefore, the binding behaviour of NS5A fragments to the SH3 domains of physiological binding partners of NS5A was studied using different biophysical methods, such as surface plasmon resonance (SPR) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy.