Synthetic nanostructures consisting of biomacromolecules such as nucleic acids have been constructed using bottom-up approaches(1,2). In particular, Watson-Crick base pairing has been used to construct a variety of two-and three-dimensional DNA nanostructures(3-10). Here, we show that RNA and the ribosomal protein L7Ae can form a nanostructure shaped like an equilateral triangle that consists of three proteins bound to an RNA scaffold. The construction of the complex relies on the proteins binding to kink-turn (K-turn) motifs in the RNA(11-13), which allows the RNA to bend by similar to 60 degrees at three positions to form a triangle. Functional RNA-protein complexes constructed with this approach could have applications in nanomedicine(14,15) and synthetic biology(14,16-18).