Combinational Biosynthesis of a Fluorescent Cyanobacterial Allophycocyanin Trimer in Escherichia Coli
|School||Qingdao University of Science and Technology|
|Keywords||Allophycocyanin Biosynthesis Recombinantprotein Fluorescence Thermalstability Escheirchia coli|
Phycobilisomes work as the light-harvesting antenna in red algae and cyanobacteria.These supramolecular protein are primarily composed of phycobiliproteins and open-chain tetrapyrroles known as phycobilins. Phycobiliproteins have been assigned to phycocyanin, phycoerythrin, allophycocyanin according to their absorption spectral properties.Phycoerythrocyanin is primarily found in certain filamentous which have no phycoerythrin.In the core of phycobilisome,there exists allophycocyanin (APC) with special spectroscopic characteristics. APC is composed by a and β subunits. Allophycocyanin(APC), a cyanobacterial photosynthetic phycobiliprotein, functions in energy transfer as a light-harvesting protein. When APC’s monomers are assembled into a trimer, a strong red-shift in the absorption and emission maxima.In this study, the pathway for the biosynthesis of holo-a and β subunits of APC from Thermosynechococcus elongatus BP-1and Synechocystis sp. PCC6803was reconstituted in Escherichia coli. A dual vector system was used to co-express the genes for apo-proteins biosythesis, the genes hol and pcyA and the genes cpcS/U in E. coli. By induction of expression, holo-a and β subunits of APC were acquired with spectroscopic properties similar to those nature protein produced in cyanobacteria.