FIGURE 2.

Alignment of sequences and secondary structure elements of the cytidylyltransferase family. The aligned sequences are as follows: GCT from B. subtilis (P27623); domains N and C of CCT from Rattus norvegicus (P19836), Ciona intestinalis (XP 002130773) (This sequence is a translation from the Ciona genome. The others are from cloned cDNAs.), Caenorhabditis elegans (P49583), Arabidopsis thaliana (Q42555), Saccharomyces cerevisiae (P13259), and Plasmodium falciparum (P49587); ECT (residues 1–156) from Homo sapiens (Q99447). The alignment was generated by ClustalW2 (62) and then manually adjusted. Residues within a pale gray box are conserved 6/8 times, and residues within a dark gray box are identical. Open boxes surround two sequence elements in segment N of the animal CCTs that are conserved. The secondary structure elements observed in GCT (PDB code 1N1D, gray) and CCT236 (this paper; black) are indicated above the sequence alignment. The layout with secondary structure elements was generated with Espript 2.2 (63). The active site residues involved in CDP coordination are marked with stars, and residues surrounding the choline are marked with circles.