The separated proteins were either stained by Coomassie brilliant blue R-250 or transferred onto nitro-cellulose membrane and immuno-detected with a specific His-tag antibody (GenScript code A00174), by using the alkaline phosphatase conjugate method, with 5-bromo-4- chloro-3-indolyl phosphate/nitro blue tetrazolium as chromo- genic substrates (Sigma-Aldrich).
This work focuses on the development of a molecular tool for purification of Photosystem II (PSII) from Nicotiana tabacum (L.). To this end, the chloroplast psbB gene encoding the CP47 PSII subunit was replaced with an engineered version of the same gene containing a C-terminal His-tag. Molecular analyses assessed the effective integration of the recombinant gene and its expression. Despite not exhibiting any obvious phenotype, the transplastomic plants remained heteroplasmic even after three rounds of regeneration under antibiotic selection. However, the recombinant His-tagged CP47 protein associated in vivo to the other PSII subunits allowing the isolation of a functional PSII core complex, although with low... More