 RBM-5 is a multi-domain RNA binding protein that regulates alternative splicing of genes important for apoptosis and cell proliferation. It has been implicated in cancer and contains structural modules for RNA recognition, such as RIM domains and a ZN finger, and protein-protein interactions, such as an OCI domain. We studied the binding of its RM1, ZNF1, RM2 domains to CIS regulatory RNA elements and found that they cooperatively recognize a GG denucleotide in a non-canonical fashion. Additionally, while the RM1, ZNF1 domains form a single structural module, the RM2 domain is connected by a flexible linker and tumbles independently. However, all three domains participate in RNA binding and a doctor closed architecture upon RNA binding. Interestingly, we observed significant differences in coupling of the RNA binding domains between the closely related homologs RBM-5 and RBM-10. This article was authored by Komol Sonny, Pravin Kumar Angush Jogtop, Santiago Martinez-Lumbaris, and others. We are article.tv, links in the description below.