The two possible stacked forms differ in which pairs of the arms are stacked with each other; which of the two dominates is highly dependent on the base sequences nearest to the junction. Some sequences result in an equilibrium between the two conformers, while others strongly prefer a single conformer. In particular, junctions containing the sequence A-CC bridging the junction point appear to strongly prefer the conformer that allows a hydrogen bond to form between the second cytosine and one of the phosphates at the junction point. While most studies have focused on the identities of the four bases nearest to the junction on each arm, it is evident that bases farther out can also affect the observed stacking conformations.