FIGURE 1.
Comparison of archaeal and eukaryotic Box C/D enzymes. (A) Two different structural models have been proposed for the archaeal Box C/D enzyme loaded with substrate RNA: the mono-RNP model and the di-RNP model. (B) The eukaryotic Box C/D enzyme has been found to assemble as a mono-RNP in its substrate-free form. Snu13, of which only one copy is present in Box C/D snoRNPs capable of methylation (upper panel), has been found to bind snoRNA with a 2:1 stoichiometry in snoRNPs that are not involved in 2′-O-methylation (lower panel).
