Expression of phycobiliprotein genes in Escherichia coli

The cpcA and cpcB genes, which encode the α- and β-subunit apoproteins of Synechococcus 7002 phycocyanin (PC), respectively, are efficiently expressed in Escherichia coli. Studies performed with a series of deletions produced from the parental plasmid pAQPR1 suggest that transcription of these genes in E. coli is initiated from a promoter located not more than 384 bp upstream from the translation start of cpcB. An examination of the nucleotide sequence of this region reveals a consensus E. coli promoter centered approx. 374 bp upstream from the cpcB translation start. The cyanelle-encoded allophycocyanin α- and β-subunit apoprotein genes (apcA and apcB) of Cyanophora paradoxa are also expressed in E. coli.