Figure 1.

Alignment of all 5 Arabidopsis SERKs, three Arabidopsis NIKs and M. truncatula SERK and SERK-like amino acid sequences. The positions of exon boundaries are shown on each sequence with a red vertical line. Exon numbers are shown in red text below the sequence alignment. Positions of SERK protein domains are shown above the alignment. Boxed areas with Roman numerals indicate the 10 subdomains of the kinase domain. Conserved leucines of the leucine zipper are highlighted blue. The SPP motif of the SPP domain is highlighted yellow. The conserved catalytic aspartate residue in subdomain VI of the kinase domain is highlighted green and the conserved arginine of RD protein kinases immediately preceding the conserved asparatate is indicated with an R above the alignment [68]. The activation loop in subdomains VII and VII is shown in red text.