Morphology of a novel cyanobacterium and characterization of light-harvesting complexes from it: Implications for phycobiliprotein evolution

Abstract

The morphology of the marine cyanobacterium DC-2 and 2 light-harvesting complexes from it were characterized. DC-2 has an outer cell wall sheath not previously observed, the purified phycoerythrin shows many unusual properties that distinguish it from all phycoerythrins characterized to date, and isolated phycobilisomes have a single absorption band at 640 nm in the phycocyanin-allophycocyanin region of the spectrum. DC-2, rather than being a member of the Synechococcus group, should be placed in its own taxonomic group. The particular properties of the isolated phycoerythrin suggest that it may be representative of an early stage in the evolution of the phycoerythrins. These observations are of special interest in light of the contribution DC-2 and related cyanobacteria may make to global primary productivity.