Fig. 7. Ribbon presentation of the model of the intact LicT protein using the coordinates of the crystal structures of the CAT domain (Declerck et al., 1999) and the PRD (this study). The individual monomers are in yellow and red. The N-terminus (N) of the PRD and the C-terminus (C) of the CAT domain are indicated. The model was created by first aligning the 2-fold axes dimer of the CAT and PRD domains and then approaching at best the C-terminus of CAT and the N-terminus of PRD. The RNA-binding surface as determined by NMR footprinting and site-directed mutagenesis is also indicated (Manival et al., 1997).