Crystallization of small RNA Hairpin Structures

[cgh24]

The RNA GUAA Tetraloop attached to a short RNA helix has not been successfully crystallized. I'm trying to understand why this hasn't been possible. The only reasoning I've been able to come up with online and textbook research is that perhaps when the strands are cooling down and annealing they bond with neighboring RNA sequences instead of the sequence from their own chain, preventing the presentation of the hairpin in any crystals that form. Am I overlooking anything from the crystallization process of RNA, or does anyone else have any ideas?


ex. of GUAA Tetraloop is attached