RNA-binding domains of the deduced PfPuf proteins and other short repeats of PfPuf1. PfPuf1 and PfPuf2 sequences were deposited in GenBank with accession nos AY098937 and AY099486. (A) Short repetitive sequences of PfPuf1. Four types of short repeats are aligned and their locations in the protein and consensus sequences indicated above the sequences. (B) Alignment of Puf domains (eight imperfect repeats) of five Plasmodium Pufs and Drosophila Pum. Plasmodium Puf genes are PfPuf1 (Pf1), PfPuf2 (Pf2), P.yoelii Puf1 (Py1), P.yoelii Puf2 (Py2) and P.knowlesi Puf2 (Pk2). Matching amino acids (at least 4 of 6) are shaded and gaps (–) are introduced to optimize alignment. Asterisks indicate amino acids that are likely to confer RNA binding specificity. Three boxes, labeled H1, H2 and H3, respectively, indicate regions that were determined to form three α-helices in Pum and human Pumilio1.