Figure 2.

Gene neighborhoods, domain architectures and contextual information graph of MORCS and related GHKL families. A) The gene neighborhoods are shown for selected MORCs (left panel) and paraMORCS (right panel). The direction of arrows indicates transcriptional direction and dots indicate intervening regions that might contain additional genes. Representative gene names are shown below each operon type. B) Representative domain architectures of MORCs and related proteins are shown. SMC_hinge: Structural maintenance of chromosome protein hinge domain; HTH: helix-turn-helix domain; BAM: Bromo-associated motif (also known as bromo-associated homology domain); TAM/MBD: C-methyl-DNA-binding domain; Z1, Z2, Z3 and X1, X2, X3 are uncharacterized domains. C) Ordered graph showing contextual information from gene neighborhoods and domain architectures. Solid arrows indicated information from domain architectures and dotted lines indicate information from gene neighborhoods. The direction of arrows denotes the order of genes in operons or order of domains in proteins from N-terminal to C-terminal. Red edges correspond to physical interactions between the domains. Genes are shown with hexagons and domains are shown as rounded rectangles. The domain coloring highlights the major contextual themes that are consistently seen with these proteins even if the actual domains belong to different families or are structurally distinct. For example, domains occurring only in eukaryotes are in yellow, nucleases are colored pink, methylases in green and non-GHKL ATPases in blue. Standard gene names are used. Additional Gene name abbreviations include: DAM: DNA Adenine Methylase; DCM: DNA Cytosine Methylase; HKD: possible nuclease domain of Phospholipase D fold; NRE: Novel Restriction Endonuclease; T2ENDO: Type II Endonuclease; pMORC: paraMORC; AIPR: Abortive infection phage resistance protein, a protein commonly encoded by numerous RM operons. Species abbrevations are as in Figure 1. Additional abbreviations are as follows: CPel: Candidatus Pelagibacter; Esp.: Erythrobacter sp.; Fjoh: Flavobacterium johnsoniae; Gura: Geobacter uraniireducens; Nmob: Nitrococcus mobilis; Otau: Ostreococcus tauri; Rsp.: Roseovarius sp.; Veis: Verminephrobacter eiseniae.