The phycocyanin-associated rod linker proteins of the phycobilisome of Gloeobacter violaceus PCC 7421 contain unusually located rod-capping domains.
Gloeobacter violaceus PCC 7421 is a unique cyanobacterium that has no thylakoids and whose genome has been sequenced [Y. Nakamura, T. Kaneko, S. Sato, M. Mimuro, H. Miyashita, T. Tsuchiya, S. Sasamoto, A. Watanabe, K. Kawashima, Y. Kishida, C. Kiyokawa, M. Kohara, M. Matsumoto, A. Matsuno, N. Nakazaki, S. Shimpo, C. Takeuchi, M. Yamada, S. Tabata, Complete Genome Structure of Gloeobacter violaceus PCC 7421, a cyanobacterium that lacks thylakoids. DNA Research 10 (2003) 137-145]. Phycobilisomes of G. violaceus were isolated and analyzed by SDS-PAGE followed by N-terminal sequencing. Three rod-linker subunits (CpeC, CpeD and CpeE) were identified as predicted from the genome sequence. The cpcC1 and cpcC2 genes at order locus named (OLN) glr0950 and gll 3219 encoding phycocyanin-associated linker proteins from G. violaceus are 56 and 55 amino acids longer at the N-terminus than the open reading frame proposed in the genome. The two amino acid extensions showed a 66% identity to one another. Also, the N-terminal extensions of these sequences were similar to domains in both the rod-capping-linker protein CpcD2 and to the C-terminus domain of the phycoerythrin-associated linker protein CpeC. These domains are not only unusual in their N-terminal location, but are unusual in that they are more closely related in sequence similarity to the C-terminus domain of the phycoerythrin-associated linker, CpeC of G. violaceus, than to the C-terminus domain of phycocyanin-associated linker CpcC in other cyanobacteria. These linker proteins with unique special domains are indicators of the unusual structure of the phycobilisomes of G. violaceus.
Gutiérrez-Cirlos
Emma Berta
EB
Unidad de Biomedicina FES-Iztacala UNAM Av. De los Barrios 1, Los Reyes Iztacala, Tlalnepantla, Edo de México 54090, México.
Pérez-Gómez
Bertha
B
Krogmann
David W
DW
Gómez-Lojero
Carlos
C
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics*; D000458:Cyanobacteria / Q000378:metabolism*; D045342:Light-Harvesting Protein Complexes / Q000235:genetics*; D008969:Molecular Sequence Data; D045524:Phycobilisomes / Q000737:chemistry*; D010798:Phycocyanin / Q000378:metabolism*; D010799:Phycoerythrin / Q000378:metabolism; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment
D001426:Bacterial Proteins; D045342:Light-Harvesting Protein Complexes; D045524:Phycobilisomes; C082501:cpcD phycobilisome linker protein, cyanobacteria; D010798:Phycocyanin; D010799:Phycoerythrin