Figure 1.

Sequence similarity and cleavage sites of the plasmodial calcineurin A (CnA) subunit. The P. falciparum (Pf) CnA sequence has been described in the Results. The accession numbers of other CnA sequences are: T. gondii (Tg) AAM97278, Paramecium tetraurelia (Pa) AF014922, H. sapiens (Hs) NP_000935. The sequences were aligned using the ClustalW program at the European Bioinformatics Institute (EMBL) server, and later refined by visual inspection. The numbers of amino acid residues are shown on the right. Residues that are identical or conservatively replaced (ST, AGILMV, DE, HKR, NQ, FWY) in all four sequences are highlighted in gray. The catalytic core, the CnB-binding, CaM-binding and the autoinhibitory domains are so marked based on studies of human CnA [15, 16, 19, 21, 25]. The catalytic domain is boxed. Residues that interact with the CsA-CyP complex are asterisked [24, 25]. The cleavage site of the plasmodial enzyme is marked by the closed triangle (between E527 and R528). Antibodies were made against synthetic peptides of the sequence TEEPPDYKALRDHLKKEGR, NCSMNDTDEGINDIV and RTLRKENELIVQLKGCSPG as shown, and used in immunoblot analysis in Fig. 3. The insertions in the Plasmodium and Toxoplasma sequences have been deleted for the sake of multiple alignment and space, but are shown on the bottom; the open triangle marks their location. The % numbers at the end represent amino acid identities of the Plasmodium sequence with the others.