Preliminary Study Of Mutant Of Electron Carry Protein (Fd) In Cyanobacteria Photosystem

The [2Fe-2S] Ferredoxin (Fd) in cyanobacteria is a kind of acidic-soluble iron sulphur protein which distributed over the surface of thylakoid membrane. As the electron carrier protein of photosystem, Fd involved directly in the electron transport of metabolism of CO2 fixation, nitrate reduction, sulfate reduction, glutamate synthesis and photophosphorylation. The research of photobiological hydrogen production in green algae discovered that Fd is responsible for the electron transport between photosystem and hydrogenase system. Limit work also suggest that Fd is a key target protein in the hydrogen metabolim in cyanobacteria.In this study, the homologous integration plasmid vector pUC-HATHF and pUCFSF were constructed using Synechococcus sp.PCC 7942 as host cell. The cmpABCD genes, which encoded an ABC-type HCO3- transporter involved in cyanobacterial CO2 concentrating mechanism (CCM),were cloned into plasmid pUC19 to generate plasmid pUC-HAT. By inserting hygromycin B pho transferase (hpt) cassette and a Synechocysis sp.PCC6803 petF cassette into the coding region of cmpABCD +1508-+1509 into pUC-HAT, the homologous integration plasmid vector pUC-HATHF was constructed. Mutant strain PF was screened after pUC-HATHF was transformed into Synechococcus sp. PCC 7942.To construct the mutant PF1, a homologous integration plasmid pUCFS which contain a strepmycin resistance gene inserting in the homologous fragment Synechococcus sp.PCC 7942 fedI was constructed and used to transform mutant PF. The method of site-directed mutation on Synechocysis sp.PCC6803 petF was applyed to constructe the mutant PFN66.And the homologous integration plasmid vector pUC-HATHF-HoxE was applyed to constructe the mutant PF-HoxE . By the comparative research between the Synechococcus sp.PCC7942 wild and mutant strains, distinguishable...