Domain organization and sequence alignments of Arabidopsis CAN1 and CAN2 proteins. The amino acid sequence alignment of two Arabidopsis CAN nucleases with conserved motifs of five bacterial proteins. The alignment contains the full-length sequences of CAN1 and CAN2 proteins and parts of the bacterial proteins showing the highest similarity to the corresponding regions of the CAN1 and CAN2 sequences (brackets above and below the sequences). AtCAN1 – CAN1 nuclease of A. thaliana [TAIR:At3g56170]. AtCAN2 – CAN2 nuclease of A. thaliana [TAIR:At2g40410]. Sg ABCt - putative periplasmic component of an ABC-type transporter of Syntrophobotulus glycolicus [NCBI:YP_004267097]. Ec CtRS - cysteinyl-tRNA synthetase of Escherichia coli [GenBank:EGW73615]. At CtRS – putative cysteinyl-tRNA synthetase of Anaerolinea thermophila [NCBI:YP_004174706]. Ct ParB - parB-like nuclease of Cronobacter turicensis [NCBI:YP_003212717]. Sa Nuc1 - thermonuclease of Staphylococcus aureus [GenBank:EGS91983]. Identical and highly conserved amino acids are boxed in black and gray, respectively. Black square (■) - the N-terminal glycine in the putative N-myristoylation motif. Open square (□) - cysteine residues in the putative palmitoylation motif. Plus sign (+) – residues, which in cysteinyl-tRNA synthetases interact with anticodon-loop bases of bacterial tRNACys. Hash sign (#) – residues affecting anticodon binding stability. Black dots (●) - residues involved in binding of Ca2+ ions. Open dots (○) - residues within the active site of the SNase domain. N-SNc and C-SNc – N-terminal and C-terminal parts of a putative SNase catalytic domain, respectively.