Co-immunoprecipitation (CoIP) was performed to identify the proteins that A0913 interacts with. The thylakoid membranes were solubilized with the detergent n-Dodecyl-β-D-maltoside (DDM) before CoIP was performed using the monoclonal antibodies against the Flag tag to precipitate the target proteins. Four proteins were obtained by the CoIP as revealed by SDS-PAGE analysis . Immunoblotting with antibodies against CP47 and the Flag tag revealed that the top band in the gel was CP47 while the third band from the top down was A0913CF . Mass spectrometry revealed that these bands were CP47 of PSII。