RNA-molecules form a variety of different structures and here is one of the more unusual ones: a quadruplex formed by the interaction of guanines form four different stretches of the molecule. (The importance of guanine residues for such a structure implies that it can only form in G-rich stretches of RNA-molecules.) In the example presented the quadruplex is preceded by a short stretch of an RNA double helix, as can be seen by the following lateral view of the structure. (The structure has been elucidated by Phan et al. in 2011 and has been published in Nature Structural & Molecular Biology (doi:10.1038/nsmb.2064)). In the lateral view, the double helix is given in the upper part of the structure, the quadruplex in the lower part. Guanines are given in white, all other bases in yellow color. The RNA backbone is given in black.
- RNA Quadruplex
The symmetry of the quadruplex is better conceived by a perspective form below the structure as in the following image. The colors have been assigned in this image in the same way as before.
- RNA Quadruplex