Figure 1.

In panel A, an image describes the location of the FMO complex in the light-harvesting complex of green sulfur bacteria. The photons are absorbed by the chlorosome and transported as excitations to the FMO complex and ultimately to the reaction center. In panel B one can see the crystal structure of the FMO complex monomer for Chlorobaculum tepidum (PDB: 3ENI). The protein scaffold is colored in pink for alpha helices, in yellow for beta sheets, and in blue for loops. The 8 bacteriochlorophyll a (BChl-a) pigments are colored in cyan (their side chains are not shown for simplicity).