The 8 linker-polypeptides from the cyanobacterium Mastigocladus laminosus were examined
by comparative amino-acid sequence analysis for the predicted domain structure reported in the literatur
(Glauser 1991, Esteban 1993) in detail using split sequences for the rod, rod-core and for the repeats from
the core-membrane linker-polypeptide (Lcm127.6). This analysis gives two distinct domains, where domain
1 (∼ 22 kDa, identity between 31 and 70%) is present in the N-terminal two thirds of the class II linkers
(∼ 30 kDa) and in the repeats of the Lcm127.6, and domain 2 (∼ 10 kDa, identity between 28 and 41%) in
the C-terminal part of the class II rod linkers (Lr31.5 and Lr32.5) and in the two capping linkers (Lc7.7 and Lr8.2). Based on these data, X-ray structure analysis from phycobiliproteins and proteolysis experiments, an
interlocking model for the phycobilisome rod organization is proposed, with linkers protruding from one
phycobilisome disk into the neighbouring one.
