Figure 3
Structural alignment between AtPRK3 and the SERK family of plant co-receptor structures. (A) Structure of AtPRK3 is superimposed on BAK1 (PDB ID: 4M7E) with a root-mean-square deviation (RMSD) of 1.92 Å in 154 over 208 residues. The PRK3 structure is colored in cyan and the BAK1 structure is in red. (B) Structure of PRK3 is superimposed on SERK1 (PDB ID: 4LSX) with an RMSD of 1.89 Å in 157 over 208 residues. The PRK3 structure is colored in cyan and the SERK1 structure is in magenta. (C) Superposition of the ectodomain structures of PRK3 and SERK2 (PDB ID: 5GQR) with an RMSD of 1.96 Å in 159 over 208 residues. The PRK3 structure is colored in cyan and the SERK2 structure is in orange. (D) Amino acid sequence of the Arabidopsis thaliana PRK3 extracellular domain is aligned with the SERK family of Arabidopsis thaliana co-receptors, BAK1, SERK1, and SERK2. Residue numbers of A. thaliana PRK3 are indicated on the top of the sequences. The residues that are identical in all four sequences are colored in red. The residues that are similar in all four sequences are colored in blue. Similar residues are defined as: (1) negatively charged side chains as D and E; (2) positively charged side chains as R and K; (3) aliphatic side chains as L, I, and V; (4) aromatic side chains as F, Y, and W; (5) side chains with hydroxyl group as S and T; (6) amide side chains as Q and N. The definition of similar residues is adapted from the BLOSUM matrix82. The sequence identity between ecdPRK3 and ecdBAK1, ecdSERK1, and ecdSERK2 are 32.43%, 32.32%, and 30.81% respectively.
