Figure 7.

Proposed models of PBS structure for the different Synechococcus pigment types and subtypes. PBS cores are generally composed of three cylinders, but in some chromatic adapters possessing an extended L_CM, it is likely composed of two additional half cylinders (see, for example, [58]). In pigment type 1, rods are composed of C-PC only; in pigment type 2, rods are composed of either C-PC, or R-PCIII and a PEI-like phycobiliprotein; in pigment type 3, rods comprise R-PC and two PE types (PEI and PEII). Cells of the latter pigment type bind PEB and PUB at a low (3a), medium (3b), high (3c) or variable (3d or type IV chromatic adapter) ratio. Colored stars indicate the pigment type of each strain (see Figure 1 for color code).