Figure 1. Schematic representation of the three types of hemi-discoidal PBS. a, PBS with bicylindrical core. Bicylindrical core consists of two identical asymmetric cylinders arranged in anti-parallel manner, which is made up of four allophycocyanin trimer disk, arranged in sequence of T8-T-M-B8; b, PBS with tricylindrical core. Tricylindrical core consists of two types (asymmetric T8-T-M-B8 and symmetric T8-T-T-T8) of allophycocyanin cylinders. Two similar types of cylinders are arranged in same manner as in bicylindrical core, whereas third symmetric cylinder (T8-T-T-T8) is arranged on them as shown in figure; c. PBS with pentacylindrical core. Pentacylindrical core contains two extra asymmetric half-cylinders (only two trimer disks- T-T8) beside the symmetric cylinder as shown in figure, oriented in anti-parallel manner to each other. T8-disk is made up of α- and ß-subunits of allophycocyanin and core linker peptide (L_C^8.9); T-disk contains an α- and ß-subunit of allophycocyanin without any linker peptide; M-disk is composed of α-, ß- and variant ß-(16 kDa)subunits of allophycocyanin and core-membrane linker peptide (L_CM^72-127). B8-disk comprises of α-, variant α- and ß-subunits of allophycocyanin and core linker peptide (L_C^8.9).