The protein contains two RNA-binding domains which are composed of four antiparallel b-sheets connected by a-helices. RNA binds to one side of the sheet. and the a-helices occupy the other side of the sheet. Note how the RNA is bound in a highly bent conformation.
Because the RNA is single-stranded, all the hydrogen bonding groups in the bases are available to interact with the protein. In addition, there are three hydrogen bonds formed between the 2′-OH of the ribose and the protein. These hydrogen bonds account for the fact that the protein has low affinity for DNA