Comparison between tRNAs of N. equitans and Nst1. (A) Secondary structure models of Nst1 single transcript tRNAs that are transcribed from split genes in N. equitans. In red are the nucleotide differences present in N. equitans. (B) Secondary structures of tRNAs that are interrupted by an intron in both Nanoarchaeota, using the Nst1 sequence frames. The intron sequences and their insertion site (blue arrow) are indicated as well as the nucleotide polymorphisms in N. equitans (Insertions-red arrows, deletions-Δ).