The tetraloop-tetraloop receptor was identified by comparative sequence analysis. This tertiary interaction is characterized by specific hydrogen-bonding interactions between a tetraloop and a 11-nucleotide internal loop/helical region that forms the receptor. Other kinds of loop and receptor interactions, such as penta-loop/receptor and hexa-loop/receptor, are observed in our tertiary motif search. Thus, this motif is call loop-loop receptor.
Reference: Costa,M. and F.Michel. 1995. Frequent Use of the Same Tertiary Motif by Self-Folding RNAs. EMBO Journal 14:1276-1285.