Isolation of Photosystem I Reaction Center Subunit Polypeptides From Spinach

Methods to prepare photosystem (PS)I reaction center (RC) subunit polypeptides are described. For PsaC, PsaD, PsaE, and PsaY, the filtrate resulting from the ultrafiltration in Chapter 6 is used for preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). PsaA and PsaB, Type II PSI particles, prepared as described in the preceding chapter, are treated with sodium dodecyl sulfate, then applied on preparative SDS-PAGE. After electrophoresis, each band is cut out and electroeluted. A simple method to prepare PsaC is also presented.