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Updated: Jul 8, 2026

In Vitro Reconstitution of Light-harvesting Complexes of Plants and Green Algae
Published on: October 10, 2014
Purification of His6-tagged Photosystem I from Chlamydomonas reinhardtii
Galina Gulis1, Kuppala V Narasimhulu, Lisa N Fox
1Department of Chemistry, University of Alabama, 206 Shelby Hall, 250 Hackberry Lane, Tuscaloosa, AL 35487-0336, USA.
Abstract:
We have developed a rapid method for isolation of the Photosystem I (PS1) complex from Chlamydomonas reinhardtii using epitope tagging. Six histidine residues were genetically added to the N-terminus of the PsaA core subunit of PS1. The His(6)-tagged PS1 could be purified with a yield of 80-90% from detergent-solubilized thylakoid membranes within 3 h in a single step using a Ni-nitrilotriacetic acid (Ni-NTA) column. Immunoblots and low-temperature fluorescence analysis indicated that the His(6)-tagged PS1 preparation was highly pure and extremely low in uncoupled pigments. Moreover, the introduced tag appeared to have no adverse effect upon PS1 structure/function, as judged by photochemical assays and EPR spectroscopy of isolated particles, as well as photosynthetic growth tests of the tagged strain.
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