Phylogenetic tree of DCD domains in plants and related domain architecture. The tree topology was calculated using the Neighbor-Joining algorithm. Hypothetical proteins putatively involved in cell death with c-terminal DCD domains (I. Genbank accession numbers in red), hypothetical proteins with central DCD domains (II. Genbank accession numbers in blue), further hypothetical proteins with N-terminal DCD-domains, ParB domain preceding a DCD-domain and of unclear architecture (III. Genbank accession numbers in black), Kelch-repeat containing proteins (IV. Genbank accession numbers in yellow). The not clearly grouped sequence of Thalassiosira is colored in green. The accession numbers are followed by species names (at: Arabidopsis thaliana; cp: Citrus X paradisi; cr: Ceratopteris richardii; dc: Daucus carota; gm: Glycine max; mt: Medicago truncatula; os: Oryza sativa; pp: Physcomitrella patens; ps: Pisum sativum; tp: Thalassiosira pseudonana) Numbers in nodes indicate bootstrap values (only essentials are shown). The domain names are according to the Simple Modular Architecture Research Tool [19, 20] * this sequence contains may be an incorrectly sequenced C-terminal part

Multiple sequence alignment of DCD-domains. The alignment was built using T-coffee [21] and refined manually. First column: database accession numbers (Genbank, if available); second column: species names (at: Arabidopsis thaliana; cp: Citrus X paradisi; cr: Ceratopteris richardii; gm: Glycine max; mt: Medicago truncatula; os: Oryza sativa; tp: Thalassiosira pseudonana); third column: start of the domain in the respective sequences. The aligment is coloured by chroma [22]. (conserved prolines: white on grey; conserved glycines and alanines: green on grey; conserved leucines, isoleucines, phenylalanines, cysteines, valines and tyrosines: yellow on grey; conserved asparagines and glutamines: dark red on grey; conserved glutamic acids: light red on grey; conserved threonines and serines: light blue on grey; conserved aliphatic residues: grey on yellow; conserved hydrophobic residues: black on yellow; conserved small residues: dark green on white; conserved positively charged residues: blue on white; conserved polar residues: dark blue on white; conserved charged residues: pink on white; conserved aromatic residues: blue on yellow; conserved big residues: blue on light yellow; conserved negatively charged residues: red on white) The consensus sequence (conserved in 80% of the sequences) shown below; h, p, s, l, b, c, a, + and – indicate hydrophobic, polar, small, aliphatic, big, charged, aromatic, positively charged and negatively charged residues, respectively. The predicted secondary structure taken from the consensus of the alignment (H, helix or E, beta sheet predicted with expected average accuracy > 82%; h, helix or e, beta sheet predicted with expected average accuracy < 82%) using PhD [23]. Independent predictions have been performed for Psipred 17 using representatives of distinct groups (accession number: gi|2369766, gi|50932255, gi|51535545). Asterisks on the top of the alignment indicate conserved Cystein residues (red: present in almost all DCD domains, green: present subfamily-specific)