FIG. 1.

(A) Domain structure of the R. sphaeroides AppA and PpaA proteins. SCHIC, sensor containing heme instead of cobalamin (23); BLUF, sensor of blue light using FAD (17); Cys, cysteine-rich domain; Arg, arginine-rich domain. Domains of unknown function are shown on a gray background. (B) Alignment of the SCHIC domains from anaerobic (top four) and aerobic anoxygenic phototrophic proteobacteria. Black shading indicates identities within the group; gray shading indicates similarities. The consensus is derived from a larger (58 sequences) alignment of the SCHIC domains.