We have not identified any RNA structures bound to the nucleolin protein to date. In this research work, we have elucidated, for the first time, the complex structure of RNA-bound nucleolin protein, Figure and 5. Significant structural changes were observed in the free nucleolin protein vs RNA-bound nucleolin protein. In the free state, the domains are close to each other, forming a square; however, in the presence of the RNA, the four domains arrange themself in a linear form to accommodate the RNA. The protein's electrostatic surface potential (ESP) plays a significant role in RNA binding because only the protein's positive portion interacts with the negatively charged RNA. In nucleolin, all four domains bind to RNA, similar to other RNA-binding proteins that also engage multiple domains in RNA interaction.