Figure 4.

Structural conservation among fungal and Plasmodium RNA triphosphatases. The amino acid sequence of P. falciparum Prt1 is aligned with the sequences of the catalytic domains of fungal RNA triphosphatases of S. cerevisiae Cet1, C. albicans CaCet1, S. cerevisiae Cth1, and S. pombe Pct1. Gaps in the alignment are indicated by dashes. The β-strands that form the triphosphate tunnel of Cet1 are denoted above the sequence. Peptide segments with the highest degree of conservation in all five proteins are highlighted by the shaded boxes. Hydrophilic amino acids that comprise the active site within the tunnel are denoted by dots. Conserved motifs A (β1), B (β9), and C (β11) that define the metal-dependent RNA triphosphatase family are indicated below the sequence. The polyasparagine insert in Prt1 is omitted from the alignment and denoted by a triangle under the sequence between strands β6 and β7.