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  • O. Neuschaefer-Rube
  • M. Westermann
  • M. Bluggel
  • H.E. Meyer
  • A. Ernst
The cyanobacterium Synechocystis sp. strain BO 8402, isolated from Lake Constance, lacks phycobilisomes but instead forms inclusion bodies containing remnants of phycobiliproteins. The inclusion bodies are surrounded by a proteinaceous capsule and contain alpha-phycocyanin and beta-phycocyanin, the rod linker polypeptide (LRPC)-P-35 and a novel blue-colored protein L-55 with an apparent molecular mass of 55 kDa. An antibody raised against beta-phycocyanin showed a strong cross-reaction with L- 55. Mass spectrometry analysis of proteolytic peptides from L- 55 revealed mass identity to proteolytic peptides derived from (LRPC)-P-35 and beta-phycocyanin. However, analysis of the genome of strain BO 8402 revealed only one cpcBACE operon, encoding the apoproteins of beta-phycocyanin and alpha- phycocyanin, (LRPC)-P-35 and a subunit of the phycocyanin alpha subunit phycocyanobilin lyase, respectively. The gene structure, sequence and transcription of these genes were identical to that of a revertant strain, Synechocystis sp. strain BO 9201, which formed phycobilisomes and did not express L-55. Based on these observations, we concluded that L-55 did not derive from a particular gene or from a special form of mRNA-processing. We propose that L-55 is formed by post- translational fusion of (LRPC)-P-35 and beta-phycocyanin. Cross-linking may stabilize the formation of the large paracrystalline phycocyanin aggregates unique to Synechocystis sp. strain BO 8402. [KEYWORDS: cross-link; inclusion body; phycobiliproteins;post- translational fusion; Synechocystis sp strain; BO 8402 Mastigocladus-laminosus phycobilisomes; subunit phycocyanobilinlyase; light-harvesting complexes; crystal-structure analysis;c-phycocyanin; rod substructures; core substructure; bilin attachment; gamma-subunit; 2.2 angstrom]
Original languageEnglish
Pages (from-to)3623-3632
JournalEuropean Journal of Biochemistry
Issue number12
StatePublished - 2000

ID: 354629