The ycf27 genes from cyanobacteria and eukaryotic algae: distribution and implications for chloroplast evolution.
The two ycf27 genes from the filamentous cyanobacterium Tolypothrix PCC 7601 have been cloned and sequenced. These two genes, previously designated rpaA and rpaB, encode putative transcriptional regulators of the 'OmpR' family. In Synechocystis PCC 6803, homologous genes have been linked to the regulation of transfer of excitation energy from the phycobilisome to photosystem (PS) I and PSII respectively. Partial clones from Spirulina platensis, Dactylococcopsis salina and Synechococcus PCC 7002 have also been sequenced. A table of identity between the proteins confirms that RpaB belongs in the same family as the algal ycf27 proteins. However, RpaA is a rather different protein and should lose the designation ycf27. The loss of rpaB from the plastid genomes of eukaryotic algae is associated with the loss of phycobiliproteins, so it is likely that this gene performs a similar role in algae to that in cyanobacteria. The implications for chloroplast evolution are discussed along with the possible identity of the cognate histidine kinase gene in the plastid genomes.
Ashby
Mark K
MK
Department of Basic Medical Sciences, Biochemistry Section, University of the West Indies, Kingston, Jamaica. mark.ashby@uwimona.edu.jm
Houmard
Jean
J
Mullineaux
Conrad W
CW
D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D005075:Biological Evolution; D002736:Chloroplasts / Q000235:genetics*; D003001:Cloning, Molecular; D000458:Cyanobacteria / Q000235:genetics*; D056890:Eukaryota / Q000235:genetics*; D005057:Eukaryotic Cells; D015964:Gene Expression Regulation, Bacterial; D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; D045524:Phycobilisomes; D010940:Plant Proteins / Q000235:genetics* / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D017422:Sequence Analysis, DNA; D015398:Signal Transduction; D015534:Trans-Activators / Q000235:genetics* / Q000378:metabolism
D001426:Bacterial Proteins; D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; D045524:Phycobilisomes; D010940:Plant Proteins; D011506:Proteins; D015534:Trans-Activators; C112177:osmolarity response regulator proteins