Alignment of MB2 S1 domains with representative S1 domain sequences. Representative sequences containing an S1 domain are PNP/Ecoli: polyribonucleotide phosphorylase (PNPase), Escherichia coli [P05055/622–711], Stress/Li: protein similar to B. subtilis general stress protein 13, Listeria innocua [NP_471798/7–103], 30S_S1/Ll: 30S ribosomal protein S1, Lactococcus lactis lactis [NP_266994/195–312], S1/hu: ribosomal S1 protein, human [AAA97575/154–223], eIF2a/hu: eukaryotic initiation factor 2 alpha subunit, human [P05198/17–121], eIF2a/Pf: Putative eukaryotic initiation factor 2 alpha, Plasmodium falciparum [PF07_0017/20–138], identified from PlasmoDB database. MB2 S1 domains are included from six species: Pf = P. falciparum, Pk = P. knowlesi, Pg = P. gallinaceum, Pb = P. berghei, Py = P. yoelii, Pc = P. chabaudi. The secondary structure determined for PNPase  is represented above the alignment with a α helix indicated by a cylinder and β sheets indicated by thick lines. The structure predicted for PfMB2 is represented below the alignment. Black triangles indicate highly conserved residues identified by Bycroft et al., . Asterisks indicate sequences identified by BLAST search with MB2 sequences. Alignment generated using the Clustal method (DNAStar). Similar amino acid residues are shaded.