The human genome encodes more than 1500 RNA binding proteins (RBPs) that regulate key processes, including translation, localisation, stability and splicing . In order to understand fully the structure-function relationship of an RBP, it is necessary to identify to which RNAs it binds in vivo, and how non-covalent interactions occur in the binding site. RNA-protein binding occurs at conserved RNA binding domains, such as RNA recognition motifs (RRM), heterogeneous nuclear ribonucleoprotein (hnRNP) K-homology domains and zinc finger (ZnF) domains . These domains recognize short, usually single-stranded regions of 3-8 nucleotides (nt) known collectively as consensus RNA binding elements (RBE) that often contain degenerate positions. Additional binding affinity and selectivity can be generated via supplementary contacts between the RNA and the protein ; for example, the RBP FUS has a bipartite binding mode comprising its ZnF domain and its RRM . RNA-protein binding