Fig. 7

Alignment of primase motifs from bacteriophage T7 gp4 and various Twinkle helicase homologues. Conserved primase motifs (I-VI and RNA polymerase basic; RNA Pol) are those observed by Ilyina, Gorbalenya [64] and Shutt and Gray [10], while the critical residues for T7 gp4 primase activity [36, 37] are shown (arrows). Identical and similar residues (compared to the T7 gp4 sequence) are shaded in black and grey, respectively. Parentheses indicate the number of residues flanking each motif. Proteins from the following sources were used: Arabidopsis thaliana (At; NP_849735), Dictyostelium discoideum (Dd; XP_636842), Homo sapiens (Hs; NP_068602), Mus musculus (Mm; NP_722491), Plasmodium falciparum (Pf; XP_001348285) and bacteriophage T7 (NP_041975)