CDAT8 is responsible for C-to-U editing at position 8 in tRNA. It is composed of three domains: an N-terminal cytidine deaminase domain (CDD), a central ferredoxin-like domain (FLD), and a C-terminal THUMP domain. Works as a dimer. In Methanopyrus kandleri, only four tRNAs (tRNAGln UUG, tRNAPro GGG, tRNAPro UGG, and tRNAThr GGU) possess a U8 (T8 in the tRNA gene), whereas the other 30 tRNA genes encode C8. The highly conserved U8 in tRNAs forms a reverse Hoogsteen tertiary base pair with A14 that stabilizes the sharp kink between the acceptor stem and base A9. The C8 must be modified to U in order to support the tertiary interaction with A14, which is present in all 34 tRNAs.