Fig. 3. N-terminal domains of Rad9 are comparatively well conserved in other yeast species. Rad9 orthologues in two divergent budding yeasts (Saccharomyces castelli and Saccharomyces kluyveri) were obtained from the Saccharomyces Genome Database. Amino acids 40-200 of the three Rad9 orthologues were aligned with amino acids 40-200 from S. pombe Crb2 using the ClustalW algorithm. Perfectly conserved residues are highlighted in black, structurally similar residues are highlighted in grey.