Amino acid sequence conservation of the IQ67 domain. Aligned are sequences of the IQ67 domain of 72 putative IQD proteins form Arabidopsis thaliana (a), Oryza sativa (b), Pinus spp. and Physcomitrella patens (c). Each protein is identified by its gene identification (Arabidopsis and rice) or accession number (pine and moss). The numbers above the scheme (1–67) indicate the position within the domain as defined in this study. The position of the conserved phase-0 intron that separates the coding region of the IQ67 domain between codon 16 and 17 is marked by an arrow. The shading of the alignment presents residues (white text) of the IQ motifs (red), the 1-5-10 motifs (blue) and the 1-8-14 motifs (green). If a residue is part of more than one motif, the residue is shaded in the first assigned color as determined by the order of motifs listed above. In addition, acidic, basic and hydrophobic amino acid residues that are conserved in at least 50% of the 72 sequences are shaded in grey, pink and yellow, respectively. The scheme of connected triangles below panel C depicts the position and boundaries of the IQ (red), 1-5-10 (blue) and 1-8-14 (green) motifs. The consensus sequence at the bottom is based on the residues with greater than 50% conservation among the 72 proteins shown (#, hydrophobic; +, basic). Black braces at right indicate the major subfamilies as defined by the phylogenetic analysis of the 72 IQ67 domain sequences in Figure 7. Accession numbers of the putative pine and moss IQD proteins are given the prefixes 'Ps' and 'Pp', respectively.