The domains of polypyrimidine tract binding protein have distinct RNA structural preferences

Hairpin loops from c-src and GABAA [gamma]2 pre-mRNAs and from the 3' terminus of hepatitis C virus (HCV) were compared to a single-stranded polypyrimidine tract from GABAA [gamma]2 pre-mRNA to understand the modular binding function of structured or unstructured polypyrimidine tract binding protein 1 (PTB1) RNA. The structured or single-stranded binding of short and long polypyrimidine tracts provided insights into the versatile role of PTB as an adaptor protein that facilitates formation of RNA-protein regulatory complexes.